Didn't Generations also imply that he had a short retirement between TMP and TWOK?
The implication was in the form of Kirk speaking of "returning". This can be taken two ways: either Kirk did go away and then return - or then he never took any sort of leave but instead returned to work as usual.
Since it's all about Kirk pondering how to deal with his bedmate after an apparently enjoyable cabin weekend, the "This time I'll
not tell her I'm going back to the office" line might well be taken to mean he had been at said office the previous Friday, and in the real universe had kept up that pattern until TUC.
As for the TUC retirement, it was a done deal at the beginning of that movie already. That is, McCoy speaks of a retirement party for "us" - although Scotty then pipes in by saying it would "suit him" fine, as if the idea just occurred to him...
At the end of the movie, Uhura tells Starfleet wants the heroes to return for decommissioning. She's apparently not speaking of the ship, as Kirk soon thereafter dictates a log where he believes the ship will sail on under a new crew. "Decommission" is a funny word for retirement, but might be apt for dishonorable discharge, or perhaps for some in-between, not-quite-voluntary means of kicking out the old fools (since Kirk in GEN clearly hasn't been
dishonorably discharged).
Kirk isn't at the TAS-canonized mandatory retirement age of 75 yet. But the "us" doing the retiring aren't of identical ages anyway. Or at least the suggestion is that Kirk, McCoy and Spock are to retire, and just possibly Scotty as well - but Uhura and Chekov aren't included in the deal in any TUC-apparent fashion. The Big Three retiring all at once, at random points of their careers, might suggest the reasons are unrelated to
a) age
b) rank or
c) personal affairs
but might be related to
d) the upcoming fate of the ship, with all being told that it's time to give room for a new command crew, and seeing this as a perfect excuse to retire en masse, even if each individual could still personally continue a career in Starfleet, or
e) some other endeavor the three have decided to share, giving up Starfleet in favor of this endeavor (of which we later hear nothing)
f) a command from on high for the three to scram, although why such a command would be coming back when the Klingon crisis is still at its height and Starfleet loves Kirk as an anti-Klingon symbol is unclear
Timo Saloniemi