Because women dont want to marry men who want to be primary stay at home dads, some do, but I have never met a woman who wants that. Most of the women I speak to when asked think its a little bit funny.
This makes a dichotomy where if a man makes $100k+ in most places in the US, they can one-income support a family. Where as women tend not to look favorably to men who take time off of to stay at home.
Women's desire for high status men is something that comes to us from being primates. It's at best a mixture of nature and society. Even if we had a radically egalitarian society, there is a part of many couples that would be unsettled by it.
All that said, there is nothing about that should stop women from pursuing careers in tech. Of all work, ours is one that is really friendly to working remotely and with flexible hours.
While resulting partnerships obviously must be reciprocal, preferences don't have to be.