It's all about choices. The more people you live with, the fewer choices you have because everyone else's wants and needs have to be considered before you do anything. In considering what everyone's unique expectations and responsibilities are, you have conflict, and who wants to live in a state of conflict where they lay their head every night? That's why people get divorced and live alone, to live in peace. It's also why there is a playroom for the kids in the basement and a man-cave in the garage, to give everyone their own space where they can make their own choices.

In traditional culures the patriarch tells everyone what to do, and there you go. He has lots of choices, but the others in the family do not. He is the boss, so there is no conflict because he won't put up with it.

I've lived in group situations beyond the family unit, like barracks, dormitories, and group homes, and I find it amazing that anyone thinks that living collectively is a good idea. Having to deal with other people's shit constantly is no way to live, unless you really love those people. If you are a person that makes believe that they love everybody, maybe you could it do it, at least until you want to kill the asshole that ate your last piece of pizza.