When I was a kid in NYC, I remember going to the newsstand with my dad and they had a few racks of the mass market comics. I'd get spider man and superman, my younger sister would get Donald Duck and similar things. Today there's no newsstand and paper media is imploding, so it's a completely different market.
I don't get manga at all, but it's a different phenomenon that doesn't have mass appeal, and girls aren't in the niche.
It's been a long time since that implosion, that isn't an excuse any longer for why comics continue to alienate new readers and reinforce stereotypes.
This hasn't been true of comic books for several decades now. The medium has many examples of high quality, well written, and unique books. Also, the demographics of comics has changed many times over the last 100 years, the focus on men over the last couple of decades is recent phenomenon in the grand scheme of things.