They couldn't, they killed the one person they had who knew exactly how it worked and Khan killed all the others who had any inkling. (except Carol) He also took all the data from the Regula Station and that got destroyed along with the Reliant when the only working torpedo blew up. David used Protomatter and kept that tidbit to himself, so there was no way that the Klingons would have been able to produce a working prototype.
If they really want the drive to fit into established continuity, it needs to be they "can't", not they "shouldn't" use the drive anymore, by series end. Otherwise they'd definitely have pulled it out for "one more trip" in situations like Voyager. I'm hoping for something more definitive than a decision not to use it anymore.
Not if the ship's computer didn't have any information on it. If it's classified they won't have information on it. I do agree with you though, I would prefer a 'Can't', but it won't bother me a whole lot of it's a 'shouldn't' if it's a decent enough reason.
Once Voyager was back in contact with Starfleet, what was stopping Admiral Paris from giving Janeway the 'classified' spore drive info?
Not every Admiral is privy to classified info that doesn't entail their particular area of command. It appeared that Paris was involved mainly with Communications, not Star Drives. Unless Adm. Paris specifically inquired if there was other tech available, there'd be no reason for him to have classified info about the Spore Drive. In fact, even the Commanding Admiral of StarFleet may not know about it if there has never been any reason in the last 90+ years for it to have come up. If anybody would be in the know, it would probably be the Admiral of StarFleet Intelligence, and again after 90+ years, it might be tucked away so deep that only Sarek and Spock would be knowledgeable about it by the time of Voyager. And we didn't see either of them involved with Voyagers predicament.
Sorry, but there’s no way that Starfleet wouldn’t have allowed Janeway to use the spore drive to get home if it was a viable means of propulsion, classified or not. It’s not something that Starfleet would have just forgotten about.
If it's never used again for a specific reason or so deeply classified that anybody but Spock & Sarek that know about it is dead and gone, after 90+ years, it could very much have been forgotten. There would probably be tales told by the Klingons of a Federation Ship that use to be able to magically appear throughout the universe, but most folks would chalk that up to too much warnog.
The Spore Drive was not built in a vacuum. 2 entire ships were built around it. Hundreds of people and thousands of hours of work were involved. The idea there is no trace of it in Starfleet's databanks or enough theoretical data for uber geniuses like Seven of Nine to reinvent it is preposterous. The idea that Starfleet, when faced with annihilation, still would not use the drive because it's unsafe to plug a human into it is intelligence insulting, even by Trek's low low standards.
It's far from certain that the Discovery and the Glenn were built around the spore drive experiment. Rather more probably, the eccentric scientists were given surplus ships to play with, along with half a dozen other eccentric scientists who were running all those other experiments Saru proudly said the ship was capable of. Eccentric scientists just deal with high energies, so they needed ships with spinning lightning rods. The project is still immensely classified as of 2257 - fewer people know of it than there are folks in the know about US bioweapon programs of, say, WWII or Vietnam era. Keeping it under the lid is not the problem. Finding the motivation to keep it under the lid is; and if the motivation gets explicated in the show, our next worry is whether this really will keep people from writing memoirs half a century after the fact, meaning somebody (hero, villain, other) will commit himself to rediscovery. Which is why it would be preferable for the project to remain a secret and be a failure. Thus, nobody would read about that desperate hour when scientists were installing cats inside bombs to serve as guidance systems and get ugly ideas: not only would the Men in Black Badges be extra careful about eliminating witnesses, but the idea would not attract anybody any longer. But we need a failure that doesn't let the spore drive serve as a means of mass destruction or bank heists or making your noisy neighbor suffer - a failure that makes people turn away from the drive for good. As for Genesis, quite possibly everybody has one in his kitchen in the 24th century. The tech was simply perfected and compacted and now serves man at the push of a button. Problems of galactic food shortage solved at much less fuss and cost than the creating of breadbasket planets would entail. Timo Saloniemi
I have a feeling that even in the 24th Century, "Protomatter" is still the quantifiable factor for ruling out anybody attempting to recreate the Genesis Device. SInce all we really know about it is that it's "highly unstable", I chalk it up to David being more than extremely lucky, that he didn't destroy the Regula Station and half the quadrant with his little addition to the experiment. Also, there's most likely nobody left alive that even knows to employ Protomatter to get the thing to work, let alone exactly what quantities should be used or in what manner since the one guy who succeeded is dead and didn't leave any notes.
Discovery was a new ship, kept in use for science during wartime. It was not a surplus ship. Details of weapons of mass destruction are still kept under the cone for the same reason that diplomatic secrets from 100 years ago generally aren't: They still pose a terrible threat and likely will for centuries. If you want the design specs of a Plungeur type submarine you can get them. The drug cartels build better ones, now. But if you start buying up hundreds of smoke detectors and old dentist office x-ray machines, you will get yourself noticed. That does not compute. The initial version of Genesis was an instant planet destroying weapon. It could even rearrange all the matter in a nebula (bad news if your star system happens to be in one). It fit inside a gym locker. Even if it led to a food replicator later, the initial version was too dangerous to ever let anyone get their hands on. But again, its a Trek thing. Why wouldn't you use that during the Dominion War? It's understandable that the borg would have no interest in the weapon. It is of no tactical advantage to wipe out everything that could be assimilated, but that doesn't mean they don't know how to make one.
I think many folks are forgetting that the "Genesis Proposal" didn't start out with the idea of using Protomatter as a main ingredient. Actually it most likely wasn't even on the bottom of the 'List of Things to Try'. It wasn't until they apparently hit a complete standstill on the project that David came up with the crazy idea of trying it, even though every ethical scientist in the galaxy had denounced its use. Something I'm sure, he failed to mention to his mother, since she was depicted as being an extremely ethical person. (even Memory Alpha states that he used it "secretly")
This ones really simple: the DASH Drive doesn't work without a tardigrade. Even Stamets needed to inject the tardigrade DNA so he could function with the drive. Since the tardigrade may not even be from this universe, that about kills it. A simple explanation to a simple continuity puzzle. I love it! No reason for fans to be in a twist now.
Except Starfleet would have had over a century to refine it so that they wouldn’t need a tartigrade. They already proved that you don’t need one in the show. That’s my whole point. Technology that allows a ship to jump to anywhere in the universe does not simply get shelved and forgotten just because there are initial setbacks or that it becomes classified for the average Joe. That’s just ridiculous. As for Genesis: how do we know that it wasn’t perfected later and that planets aren’t being terraformed in the 24th century based on its tech?