Well, is it more likely that the lack of female main characters caused few girls to play videogames, or that the lack of videogame playing girls caused the lack of female main characters? Arguably the latter, since boys form also the majority at most games without any main character. Boys just like video games more, it's not that alleged sexism sacres the girls away.

10 years before Lara Croft, there was Samus Aran.

You could also mention all the female characters in fighting games and beat 'em ups, but those are not main characters...