I remember when "Foul Deeds Will Rise" was announced how excited I was because it was a book that took place between TFF and TUC. There are very few novels that take place during those years...
There were a number of novels between TMP and TWOK.
I always loved movie era books though. I'd love to see more books between TFF and TUC because that seems to be a great untapped period of Star Trek history to me. I know the 5 year mission period is what sells though. And those are always good reads too. But I look at books also to fill in gaps in Star Trek history. Things that happened during eras we have not seen on TV and will probably never see on TV. One of the reasons I also always liked The Lost Era books and sagas, and the continuing Enterprise novels that are filling in some of the years after Enterprise and before Discovery. Not every book of course, but it's nice to have a few books here and there that fill in some of that unseen history.
When you think about, between The Counter Clock Incident (TAS) and Star Trek: The Motion Picture is 2.5 years (even though the actual refit only took 18 months, it was twice stated in TMP that Kirk had not logged a star hour and had been in his current role for 2.5 years). Then from the end of TMP to Star Trek II: The Wrath of Khan in 2285 we have anywhere from 12.5 years (2272 earliest) to 8 years (2278, as per the uniforms seen in TNG's Cause and Effect). Star Trek III picks up within weeks, if not days of the close of Star Trek II, while Star Trek IV picks up 3 months after Star Trek III in 2286. Star Trek V takes place about a 9 months to a year later in 2287 (79 years before TNG's Season 3, thus suggesting that the Enterprise-A was undergoing an upgrade or refit for about a year, although why Scotty still didn't have all the doors working????). But then we have an even longer jump in time between Star Trek V and Star Trek VI of about 3-6 years, in which Sulu has been in command of the Excelsior for 3 years, so Star Trek VI takes place in 2290 or later (although McCoy's line about being Chief Medical Officer of the Enterprise for 27 years, if you go from 2265 would put it around 2292/2293), and of course Star Trek Generations prologue is set in 2293, 78 years before the 2371 TNG portion, plus the reporter.
So it kind of makes sense that there would be more stories between Star Trek The Motion Picture & Star Trek II The Wrath of Khan as there is nearly a decade of missions to tell, where as between V and VI we only have 3-6 years. And of course after Star Trek Generations prologue, we have a 70 year gap till Encounter at Farpoint.