I have thought about this a bit lately. I am guilty of listening to the odd bit of rock and roll and I really liked The Bangles. I think it comes down to the old chestnut of childbearing. If you get a few young women together who are in their late twenties/early thirties, one or more of them is likely to want children. Even if the women only take the minimum time out, this is likely to prove a major disruption to the band's ability to rehearse, organise, perform, promote and record. I think The Bangles were a bloody good pop group, but they took a few years out - probably to raise children. Good luck to them. I hope they are successful again. Far fewer blokes are likely to give up those critical years to stay at home with their children - which gives male bands a huge advantage. Continuity is easier for male bands.
I certainly see more women playing instruments and performing music than I used to. Good luck to them. Bring 'em on.