The federation had to make up for that Janice Lester incident on ST: TOS "Turnabout Intruder" where the show came off as chauvinistic. It gave birth to Janeway.
Um, what?
We already had our first female captain (of the
Saratoga) in Star Trek IV. There were several more on TNG, including Tryla Scott, the youngest officer to make Captain at the time from 'Conspiracy,' and Geordi's mom, Silva LaForge, who perhaps not coincidentally played the
Saratoga captain in Star Trek IV. (It always made me happy that Ben Vereen was Geordi's dad.

)
IMO, we're best of retconning crazy Janice Lester's dialog to mean that Kirk's personal life wouldn't allow her into it, and that she went through some weird psychological displacement thing after which she actually wanted to live his life and prove she could do it better. (Kinda make sense in a weird, crazy way.)
Just because the 1960s weren't ready for a female in command doesn't mean the 2260s weren't.