Ancestors? It's normal now, just not where you are. A couple of centuries ago a bunch of upper class Europeans in big homes made it a point of having separate rooms for kids as means of showing off their wealth and status, and now here we are.
You can see this history quite clearly now in the old castles Royal families live in and the obscene amount of rooms they have. Who can look after an 18 room castle? Someone with money and power, that's who.
So what part of changing the basic build blocks of family connections that have existed even before we were walking on 2 legs for a 'status symbol' makes it the better option?
Its funny we like to pretend we are smarter or 'know better now'. It couldn't be any further from the truth. We don't sleep properly, we can't eat properly, we don't exercise enough and we suffer through chronic loneliness. We are the worst examples of how human beings should live.