is a difference in mindset between boys and girls.
While I can't site any sources, I believe there's plenty of evidence to suggest that girls are more cooperative while boys are more independent. This may translate to recruiting in that a top female recruit may be more willing to go and join a team full of all Americans to be part of a great team, whereas a boy may want to go somewhere where he can be the star and stand out.
TV coverage may also have something to do with it. Lots of mid-major men's basketball programs get decent TV coverage. Not as much with the women. If you want to play on TV, there are only so many options for the women's game.