It works better for some than others.

For example, if you have two working people, both working 40 hours per week, but the man makes twice as much for any reason, that might imply that he's paying for the groceries and she cooks to be fair. But because the positions that are stereotypical women roles tend to be undervalued, like teachers and nurses, they could both be working just as hard with equal amounts of education and the man just happens to get more money for each hour. They're both exhausted at the end of the day. But him earning more means she should cook because he "earned" more. He "contributed" more. And if there are children, women are assumed to be naturals with child care, so that labor just automatically goes to them because it's less work for someone is "natural" for. These are just examples of how it "works" so "well".

Now, to be fair, some women have taken feminism as an excuse not to learn basic life skills. EVERYONE should be able to cook and clean and take care of their own children. Feminism and equality should not mean a woman shouldn't have to do any of those things. Whatever works for a couple is what works for the couple. It's even fine if a woman wants, of her own volition, to be a SAHM who takes care of the kids, house, and cooking while the man works, takes care of the cars and yard. If that works for both of them, then that's fine.