Could it be a matter of games that have hyper sexualized women tend stand out and get noticed more? By their nature I imagine they would after all. I've been gaming my whole life and not very many of the games I play with female protagonists are over-sexualized (I don't think so anyway), not that I would mind at all if they were (as I rather appreciate that sort of thing, honestly).
I mean, I don't go looking for either types of characters since my taste is fairly broad, but I tend to encounter more Heather Masons, Jill Valentines and Chun Lis, than Bayonettas, B2s, and Ivys. I suppose YMMV, depending on the games you play, but I don't think that a more conservatively dressed/mannered female character would translate to poor sales. Games like Horizon: Zero Dawn and (modern) Tomb Raider games sell pretty well, I think.
I'm not naive in that I don't realize that sex sells, but when you're dealing in fantasy themes especially, style is a pretty big draw, and celebrating extremes like power and sexuality plays well into these sorts of games. It's not unlike the hulking, over-the-top masculine characters in gritty war games.
Granted, you also get boulder punching, He-man'esque Chris Redfields, and flirty, China Dress in the field wearing Ada Wongs in series' that barely benefit from over-the-top (normal) characters, but in general I think there's a very healthy variety of female and male characters in gaming that don't fall into either extreme categories and still sell decently.