You also see a similar situation with "places in society". The majority of billionaires are men, but the majority of people in prison are men too. Women in general seem to have a more "stable" place in society compared to men. It seems harder for them to climb higher but also harder for them to fall completly at the bottom. If I wanted to sum it up, it would be something like "the glass ceiling comes with a glass floor". This is just my speculation though, and not in any way a judgment of value.