The first real hint of this was Voyager, which makes sense, because it took them 23 years to get back home, quarter of a century. In the revised timeline, only 7 years, but still makes sense. How many starships fly across the galaxy in under a decade? It was a PR thing. We also know the NX-01 ended up as a museum ship after a decade in space. This was also likely a PR with the formation of the Federation and being Starfleet's first explorer and a prototype at that.
In the 1966-2005 run, these are the only examples I can think of where a Starfleet starship became a museum piece. This wasn't really a thing in the reboot trilogy. In the streaming shows, (not counting Voyager in Lower Decks), this seems to mostly be just a "Picard show" thing. I don't like the idea that starships get retired after some 10-20 years. Cars last longer than that. WTF? The whole "mileage" thing reduces a starship to a car. Are these things supposed to go toe-to-toe with the Borg, the Dominion, survive crash landings, and shit? Come on. If the "story reason" is PR, trashed but made to look nice, or just horribly outdated (no one's expecting the Ent-A to fly again, LMAO), no probs. The Defiant-A is only 26 years old by PIC S3, why is it not still flying around kicking ass? Kirk's Enterprise was 20 years old when he took command and still had the new paint smell.
In the 1966-2005 run, these are the only examples I can think of where a Starfleet starship became a museum piece. This wasn't really a thing in the reboot trilogy. In the streaming shows, (not counting Voyager in Lower Decks), this seems to mostly be just a "Picard show" thing. I don't like the idea that starships get retired after some 10-20 years. Cars last longer than that. WTF? The whole "mileage" thing reduces a starship to a car. Are these things supposed to go toe-to-toe with the Borg, the Dominion, survive crash landings, and shit? Come on. If the "story reason" is PR, trashed but made to look nice, or just horribly outdated (no one's expecting the Ent-A to fly again, LMAO), no probs. The Defiant-A is only 26 years old by PIC S3, why is it not still flying around kicking ass? Kirk's Enterprise was 20 years old when he took command and still had the new paint smell.