I just don't like the idea of Starfleet laying down new keels on what was already declared to be an old and useless design in a previous movie.
Star Trek III: The Search for Spock wrote:
Jim, the Enterprise is twenty years old. We feel her day is over.
There is no evidence that Morrow is speaking for an entire class of vessel.
herself is closer to forty years old, but the refit was introduced in 2271. Making the design itself around fifteen years old.
In 2286, the Excelsior
is still in its test-run phase and there's no way they'd already have them in production without knowing if transwarp drive was practical. So there's no doubt in my mind that Starfleet was continuing to produce Connies until, at least, the early 2290's.