Within TOS' continuity it looks like Pike commanded the Enterprise for about ten years or so if we go by what we hear in "The Menagerie."
A minimum of "eleven years, four months, five days," since that's how long Spock served under Pike.
We don't know what happened to any of the others we see from "thirteen years ago." We can assume they remained with Pike for some years before some or all of them eventually moved on somewhere else. It certainly looks like none of them (other than Spock) remained when Kirk took over.
Although
Strange New Worlds has established Cadet Uhura and civilian specialist Chapel as members of Pike's crew, along with Dr. M'Benga. Similarly, in my novel
The Captain's Oath, I established that Uhura was on Pike's crew toward the end of his tenure. It made sense that at least a couple of people would've been holdovers.
It becomes less credible if we see TMP taking place about ten years after TOS with maybe a second 5-year mission in there. And that was apparently the original intention for the film to allow them to reflect the againg of the original cast.
What gives you that idea? TMP is explicit that Kirk served "five years out there" and that only two and a half years have elapsed since then (or 2.8 years per the novelization). The idea of a second 5-year mission between TOS and TMP is purely a fan invention, and an implication in several 1980s novels.
If we want to establish original intention, the place to go is the
Phase II Writers/Directors Guide from 1977. My copy states explicitly that the series would have depicted Kirk's
second 5-year mission on the
Enterprise, not the third, and that Kirk has refused promotion to admiral to command the ship after its refit. So the time gap between series was always meant to be shorter than the real-time interval. Even if they were counting from the end of TAS in 1974, it probably wouldn't have taken 3-4 years for a refit.
Interestingly, in looking through the
Phase II bible, I find it actually addresses the very question we're discussing, why the crew would stick together for a second tour of duty (minus Spock, who wasn't expected to be a regular anymore). From its opening page:
"In fact, all of our original crew have found themselves to be very nearly legends in their own time. Few starships have ever completed a five-year mission, and none but the U.S.S. Enterprise has returned with its original crew virtually intact. Perhaps the explanation for so many of the crew volunteering for a second five years was their seeking the relative anonymity of space. Or perhaps these men or women cannot find satisfaction in an ordinary life after so many years of the highest adventure experienced by humans."
Note that this is the origin of the claim from the TMP novelization that surviving a 5YM was almost unheard of. We can presume from this that surviving two in a row would be even more unheard of -- further proof that there was only meant to be the one 5YM before TMP.
Now we get to TWOK, fifteen years after TOS, and the same personnel are still tigether and for several more years to come.
Now you're really stretching credibility.
Not really, since the implication in TWOK is that the crew have gone their separate ways and have only reunited for the training cruise as a birthday present to Kirk. A deleted scene established overtly that Sulu had been promoted to captain the
Excelsior, though that was cut. After that, they came together to steal the
Enterprise, then were outlaws together, and then were put back together on the
Enterprise-A after their pardon. I always figured that was pretty much to get them out of the way, since even after their pardon, a lot of crews might not have been comfortable working alongside them.
Then we get a big time jump to ST VI, which also indicates that the crew have come back together for a specific mission after some time apart. A deleted opening sequence would've shown Admiral Kirk recruiting them all one by one.
Still, my understanding is that the original idea behind introducing Saavik and David in TWOK was that the film series would gradually phase out the older cast in favor of new, younger leads, a more literal "Next Generation" than the one we got. Instead, nostalgia prevailed and we got a series of continuity resets rather than real growth and change.
