Shout out to the USS Thunderchild, the unluckiest and toughest ship in Starfleet
I do appreciate the more realistic lifespan, starships are massive investments that should last at least a few decades and are designed with continuous upgrades in mind (unless they're called "Enterprise" apparently).
Wait until you find out what happened to the original!
How long did the NX-01 Enterprise last?
According to Memory Alpha, 10 years because the ship was supposedly obsolete by then.
At least the OG 1701 got a good lifespan - it was no Miranda, but 40 years is great for an Enterprise.
The decommissioning of the A seemed a bit premature, though, considering it was a new ship that was relatively salvageable. Maybe its battle damage was just too much and that’s why it was given to the museum. Alternatively, the A was originally a different Constitution class undergoing a refit was was already quite old by Undiscovered country.
There’s a good chance the B lasted a long time too, though there’s no canon source to its demise, only that it’s not in the fleet museum.