Still I think canon must be forced into accepting a ten year gap between TV and TMP, as Kirk sets a fixed date in TWOK, when he tells Carol he had not seen Khan in fifteen years, which--considering the real life 1967 airdate of "Space Seed" to the 1982 release date of TWOK--is exactly fifteen years. There's not much phyisical difference between the actors from TMP to TWOK (aside from Doohan gaining a few extra pounds), so we have to assume TMP occured only a few years earlier---probably three.
If that's the case, then any published dates of TMP occuring a mere 2 years after TOS cannot be taken seriously.
I think a shorter gap between TMP and TWOK makes sense. It doesn't require Kirk to be repromoted to Admiral and the Enterprise
could have never returned to frontline service. Merely being a testbed vehicle for new technologies and then being demoted to training-ship status.
The theory of a longer gap between TOS and TMP has grown on me over the years. Also, if there's a seven to ten year gap between the two, it makes it easier to explain the radical changes we see in TMP.