No, but it could've easily passed for a new design, and the Klingon battlecruiser from ENT did retain an identical exterior in the VOY era. The producers' requirement to keep Star Trek mostly the same, as well as some budget constraints here and there, simply resulted in a similar sort of "technological stasis" that is used to explain why the Star Wars galaxy had very similar technology 25,000 years ago. Yes, there is some new technology in Star Trek, but nothing radically new. As a result, Starfleet may view starship exteriors as a set of architectural shapes, some of them repeated by tradition over generations, rather than designs driven strictly by functional requirements. The interior can change, but the exterior doesn't matter as much.
While I understand what you're getting at here, the fact of the matter is that old models were reused because of budget and time constraints, not because of some in-universe explanation that Trek is in technological stasis, even right down to the TMP bridge chair design used on a ship that was apparently built almost a century after TMP. I appreciate your attempt, as a fan, to try to explain these discrepancies, but this
fan just thinks it's utter bullshit.
The Heart of Gold, a starship mentioned in a LCARS display in "Conspiracy", has a registry of NCC-42. If registries are chronological, this starship would have to be commissioned in the mid-21st century. However, another starship from the same episode torpedoes that hypothesis. The Tycho has the highest known canonical number with NCC-85103, and this starship was active in 2364. Up to now, I, and I think a few others, thought a starship with that registry would appear after Nemesis. Nope, there it is in 2364. It's Entente all over again. Sometimes I wish that we didn't know about the starships from "Conspiracy" for they confuse matters more. I don't know how to explain the HoG.
1. Actually, the earliest the Heart of Gold
could have been commissioned is 2161, after the founding of the Federation, which would be the mid-to-late 22nd
2. If you have the registry info for all the Conspiracy ships, I'd like to know them too, especially if you have screencaps.
3. One can't explain things like this, because they were not meant to be taken seriously. They're humorous entries that will be added into my shiplist for completeness, but other than that I'm not going to lose any sleep over them. No, I don't believe Starfleet really has a ship called the Elmer Fudd
; I don't think a ship from the founding of the Federation is still operating in the TNG era; and I don't think the Tycho's
registry is really as high as what appears on that computer screen. They're all in-jokes and should be treated as such.