I think the idea only extended to TOS and (maybe) the TOS movies, although a case could be made that the Nebula- and Galaxy-classes were developed in tandem.
The argument can be made that most of the kitbashes made for Wolf 359 were at least developed in tandem, if not modular due to the fact that many have the same nacelles and similar saucers (Cheyenne and Springfield, Galaxy and Challenger).
My head canon is that the different ship families are designed/built by different "defense contractors" for Starfleet that kind of compete and that's why you have different looking starship families at the same time. In the mid-24th century you still had the Constitution-refit/Mirandas, Excelsior/DS9-kitbashes, Galaxy and Galaxy-kitbashes, Ambassador, and maybe the First Contact ships, if you go by registries. In the 2260s you had the TOS-style, the Shenzhou/Discovery style etc. The Galaxy family does their luxury sedan the Galaxy class, their hatchback Nebula class, their compact New Orleans etc. The Constitution-refit is their luxury sedan, their hatchback is Miranda, their WRX is the Constellation (maybe) etc. It's a big Federation after all.
honestly, i wouldn't be surprised if the Klingons aren't culturally against retiring a ship when it gets old, and instead always refit and continue using it until it takes too much damage to repair or is destroyed. because the ship[ has honor as much as the crew has, recorded in the Record of Battle which stays with the ship even as the crew and commanders come and go. unless a ship has just been involved in such dishonor that it cannot be recovered, i can;t see klingons being willign to retire ships with that sort of history built into them. which helps explain why they don't seem to update their ship designs very often, and why they would continue to use so many old ships.. they're taking hulls with history and giving them refits to keep them current. odds are many fo those have few original parts, but so long as the continuity of that history of battle exists, it would still be the same ship. (i also suspect that should such a ship get destroyed or just so heavily damaged that repair is not feasible, that they ritually retire the record of battle, then name a new ship the same thing with reference to the previous iteration to continue on the previous ships honor)
Given how A LOT of the classes of ships are basically same as other classes with some varying bits and bobs, to me, it seems pointless to call them a different class of ships. For example, you have the Excelsior class ships. It survived for over 80 years in active service and the 24th century versions were obviously upgraded thoroughly to the point where the 23rd century counterpart could never go toe to toe with them. Except in external aspect, it was upgraded heavily to keep it running (if the USS Lakota was any indication). Also, from what we saw in ST: Picard and Lower Decks... I fail to see why the USS Archimedes (Obena class as seen in LD) is a completely different class of ships when its predominantly based on the Excelsior and sports most or all of its design philosophy and only has a few bits that make it different than the original Excelsior (it literally sports a more oval saucer section and secondary hull... but the most important bits to note would be Sovereign class deflector, nacelles and pylons). In this instance, and compared to the original Excelsior class, the Obena isn't that much bigger... in fact the changes could easily be gotten by likely recycling older deflector and nacelles, and remaking them into Sovereing style ones... and changing the overall shape of the saucer and secondary hull to a more oval structure isn't that difficult with transporters and replicators. The external changes the Obena class is sporting seem mostly in line with what an Excelsior class might look like if it had quick late 24th century refit with pre-existing parts (I'm reminded of what Freeman said that she doesn't like it when SF starts adding stuff to a ship and makes it look like a Sovereign class - which kinda seems like it happened here - the Excelsior got an upgrade and it was Sovereigned). Similar stuff happened in ST: Picard where A LOT of ships were sporting previous design philosophy (such as from the Nebula class or even the Galaxy class ships), but otherwise were considered completely new classes as opposed to modern variants of the same class of ship (which again, wouldn't be a problem and would in fact make more sense). Take the Stargazer for example. The 25th century version of the Stargazer could have easily been said to have been the modernized Constellation class (and since the original Stargazer was indeed recovered in TNG, SF could have simply disassembled it using replicators and transporters and used that raw matter to create the 25th century version). Same applies to Excelsior II - could have been the same Excelsior class as before.. just modernized 25th century version (with the Obena being an intermediary upgrade to keep the class updated with the times until the new design for the class was ready for production). With the technology SF has, it can easily keep a same class of ships in service indefinitely. Over sufficient amount of time, externals of the ship will gradually be changed (say every 100 years or so), but the internals would undergo changes on a more frequent schedule (every 4 to 7 years). The superstructure (underlying frame of the ship) could also be easily refreshed with replicators and transporters... so even if a ship was in service for say 150 years, it could easily be the same starship that was built 150 years ago, just frequently upgraded/refreshed over time to keep it up to date. I don't see the issue with this. SF does have this capability... and as such, having so many different classess of ships that are pretty much sharing same design philosophy seems a bit pointless. Nothing says that SF cannot have a varied amount of designs... but ship classes? Eh, if a ship is based off an Excelsior and sports most of the same bits and pieces or design philosophy, then keeping it as the same class, but being a different variant of that class would make more sense. It wouldn't detract from the freedom of dreaming up new designs either way... Plus in TNG, the Nebula class had a few variants with different pods for different mission profiles. They were still the same class of ships (and that made sense). In ST: Picard and LD, the creators seem to have went nuts with giving each new starship design its own class... even if most of it is looks the same as the previous class.
I have a similar problem with the Obena class and variants like that. There is a distinction between refits and new classes, though. To me, the Sutherland class and Ross class are refits, as is the Reliant class. I see no problem with this in canon. The ship can be a new ship, but it's still a refit of a previous design. On the other hand, I would not say the Cheyenne class is a refit of the Constellation class, or the Freedom class is a refit of the Saladin class. Just like the Galaxy class and the Constitution share similar hull arrangements, these ships also share similar hull arrangements. There is a fine line between refit and new ship classes, especially when canon is vague about it, but I tend to think a refit would be when the new ship has similar or exact proportions to the old ship, it is the same era, or there are parts that match almost perfectly. The Ross class looks like a Galaxy class that was given a Sovereign face lift: almost everything looks the same but fancier, barring the secondary hull. However, the Galaxy class does not look like the Ambassador class: the shape, technology, and components are all different enough. On that note, the Constitution refit straddles this blurred line uncomfortably.
Or, it could be the same ship from when it was first constructed, just upgraded/updated over time. But SF could have just also built a new one of the same (but modernized) class for the times. The Cheyene and Freedom classes being TNG refits of Constellation and Saladin classes actually make sense to me. Why? Mainly because they have extremely close hull designs/geometries and seem to be of the same sizes - in this aspect, I don't see the problem. But correct me if I'm wrong, the Cheyenne and Freedom class ships were only seen in the aftermath of Wolf 359 attack as wreckages - but were otherwise never again seen on-screen (obviously this doesn't mean SF never used them again or abandoned the classes, just that we never got to see them). On the other hand, the Galaxy class being a refit of the Constitution doesn't make sense. In general, the Galaxy is HUGE compared to the Constitution and follows a different design flow looking at the secondary hull and the nacelle pylons. The Galaxy is sporting too many design changes compared to the Constitution to be considered a refit - though I think Disco Owoshekun mentioning a 32nd century take on the Constitution class ship which can 'sleep over a crew of 2000' (apparently) - so perhaps in TNG, SF didn't necessarily want to brand a Galaxy class as the Constitution class refit as they kept mostly the same ship sizes and very close hull shapes in the same class of ships (apparently). So, no, I can't see the Galaxy working as a TNG Constellation refit. The Titan - A however is a DEAD RINGER for a 25th century Constitution class refit though - though the amount of impulse engines it has is an overkill. I follow a similar line of thinking. If a 24th century ship has pretty much a face-lift but retains overall hull design aspects and size from say the 23rd century counterpart, then it would make more sense to just say it's the 24th century version is the same class, just that the design was upgraded to keep up with the times. Someone before mentioned for example a Galaxy class ship sporting a third nacelle from an Akira class. This doesn't make sense because the Akira class is much smaller than the Galaxy class, and its nacelle design doesn't really fit with the Galaxy class (not to mention the fact the Akira nacelle is much smaller and would likely be of no use to the Galaxy class . It would be like trying to fit an Intrepid class nacelle onto say the Sovereign class. It doesn't really work, because the Intrepid class is practically as long as a Sovereign class nacelle. The USS Archimedes (aka, Obena class - or as I like to think of it as the late 24th century Excelsior class refit - looks [to me] like an intermediary upgrade to keep the class alive and functioning until the 25th century design was ready to be rolled out so the class could be refit again), could barely get away with having Sovereign class style deflector, nacelles and pylons for example because because those components were already of similar enough size to begin with. Yes, the Sovereign class nacelles are bigger... but not by much... in this essence, scaling up the Excelsior class by just a bit wouldn't be an issue either. The ENT-E underwent physical changes in between Insurrection and Nemesis, resulting in greater number of decks, further pushed back nacelle pylons, and obviously more weapons... and if the Sovereign class can get away with that, then why not the Excelsior? In any case, I agree we have way too many different ship classes. It would make more sense to just push a lot of the different variants of the same/similar hull geometry and size into same class of ships for the the period between 23rd and 25th centuries for example... and then from that point onward, those classes of ships WOULD/could survive into the future, but would underwent significant geometry and size changes to keep up with the times.
The Cheyenne isn't a refit of the Constellation class, just like the Nebula isn't a refit of the Miranda class. Just because their components are situated in the same places doesn't mean they're the same ship. As for the four STO ships used in PIC season 2, they aren't refits of older classes either, despite the Ross, Sutherland, Reliant and Gagarin classes having the same configurations as the Galaxy, Nebula, Miranda and Shepard classes, respectively. Had I been the one to make the choices, I would have not chosen those four STO designs precisely because there's no real rational need to create brand new ship classes that aren't much different from the older classes they derived from. I would have used designs that looked like an extrapolation of where Starfleet was headed with the newest ships they had at the time (Sovereign, Nova, Prometheus.)
Then why wasn’t the Victory refit into a Cheyenne class? It was still in service in TNG, and was a Constellation class. Or the Stargazer, for that matter? Why weren’t all those old Miranda class ships we saw in DS9 TNG-fied as well?
I don't remember any of the figures off the top of my head but I think there's a pretty big differences in the sizes of the two ships, so a refit doesn't really make sense based on that.
No official canon figures have ever been released for either IFAIK, the closest available for both would be the figures given by the Official Starships Collection which suggests a variation of about 17%. Other estimates (ditl.org for instance) suggest the the Cheyenne could be as much as 71% larger but admit that this is very much speculation.
The Constellation class seems to be of comparable size to the Cheyenne. The Constellation primarily has a thick saucer rim (about 6 decks high), whereas the Cheyene's is only 1 deck high, but the Cheyenne also sports TNG style oval saucer style of the Galaxy class, so it extends to similar heights... about 6 or 7 decks in total for the saucer. Size wise and general design style wise, the Cheyenne could work as a TNG refit of the Constellation class.... you lose the saucer rim thickness, but retain the overall size of the whole ship in favour of something more modern that also might work better? In the 23rd century, I can see the thickness of the saucer rim and general size of a ship would likely remain unaffected by the refits in that era. In the 24th century however, more prominent changes to 23rd century designs would take place (thanks to replicators and transporters working together that would make external changes like that easier and faster) but general size of the ship would remain the same or close to the same (some variation would probably occur like possible addition of 1 or 2 decks - but nothing too radical that would deviate from the 23rd century version). Also, I've never really seen the Nebula class being a 24th century version of the Miranda class. In terms of whether the general shape layout is the same between the two... I can see that... but radical upscale of the Miranda to Nebula might seem a bit of a stretch from TNG SF point of view (maybe from 25th - 26th century onward, sizes of given classes of ships would be upscaled, but between 23rd and early 25th century I think SF might consider keeping the sizes of refit ship classes the same). I wonder if SF ever permanently retires a class of ships from service though.
Yes, they permanently retired the Soyuz class, despite the fact that the Miranda class continued production for at least 60-odd years.
Well, there is the minor difference that the Nebula has a considerable secondary hull (cf the Galaxy), whereas the Miranda is a pure mono-hull design (cf the Connie).
That too. Massive differences in not just overall size, but also addition of the secondary hull and deflector dish, etc. So, in this, I don't have an issue the Nebula Class being its own class of ships and not upgraded Miranda class.
I'd also peg the rarely seen New Orleans class as a better candidate for the "upgraded Connie" of the mid-24th Century as it's roughly around the same length and probably has similar facilties whereas the Galaxy-class is a step-up in both (the Connie can accommodate around 800 souls for at least short periods (2-4x standard), whereas the Galaxy can accommodate 15,000 souls for a similar period (at least 15x standard).
All we know in TNG is that the Soyuz class were retired from service and have stayed like that for a long time. As for Miranda class having continued production... maybe not. Maybe all the Miranda class ships we saw were in the field and survived for 80-odd years, just internally upgraded over time. I doubt that SF would have bothered constructing outdated 23rd century designs in the 24th century. Upgrading existing ones in service? Yes. Building new ones with designs from a century ago? Not unless the class underwent design changes that would make it worthwhile to produce the thing in bulk. SF already had a whole bunch of other ship classes (modern ones) to pick from in TNG era for construction. Why bother with outdated Mirandas? It would service and upgrade them yes, but build new ones? Not with so many other classes of ships being available (and probably superior). SF may have wanted to retain the Miranda in service... in which case, it would likely expend some resources to do a 24th century refit of the design/class to bring it into modern era (worthy of continued ship production).
Speaking of which, we could probably tolerate minor size variations i.e. Excelsior vs Obena given the variation in scaling issues seen in BoPs down the years.