Women do it like this because the alternative is nothing gets done. Men see themselves as more important. They do the things they want to do, and leave everything up to the women. e.g. man likes gardening, does the gardening and then expects the woman to do all the other shit, because he doesn't want to do it and he's more important.
I earn about 80% more than my kids' dad. I own the house outright. We are not together anymore but he hasn't moved out yet. With the exception of things that HAVE to get done, e.g. pick-up from school, one parent being home when the other is out, he does absolutely nothing for them. NOTHING. Not interested in school, doesn't know their friends' names, teachers' names, birthdays etc. Doesn't know which is the uniform drawer because he's never had to. Doesn't know contact details for doctor, piano teacher, any clubs or afterschool activities. Doesn't have contact details for any friends' parents. Doesn't arrange anything at all, e.g trip to the cinema, the park. He won't even come if I'm arranging and paying for everything, because he can't be bothered if he can just sit at home staring at a screen instead. He doesn't care, and there's no point in trying to make him care, because he just doesn't. No idea why he had kids, except possibly so he didn't have to pay his own way.
Why then do I do everything? Because the alternative is that my kids go without. He won't let them starve, but I don't just want to keep them alive. I want them to have friends, hobbies, do well in school, learn new things etc. I have to do all of that because he won't, and I won't neglect them. Yes, it's awful that they are growing up in a household where these old-fashioned roles are taking place, but unfortunately it's the least worst option. And, to be honest, the world isn't likely to change a huge amount between now and when they have their own kids.
So I suppose the answer is that we let men get away with it because we care about our kids, and we'd rather take care of them and raise them well than leave them to be neglected.