Human beings are designed not to be brought up by their parents, but by their grandparents, and other elders in the tribe/band/group. The parents are usually working outside. The great contribution elders make to the species is not in hunting or gathering, but in the education of the young and the freeing for other labor of the young adults. They may lack the physical capacity to help provide or fight for the group, but they are perfectly suited to take care of kids and teach them. This is why evolution has created us the only species of primate which tends to survive way past its reproductive years. It is also why all surviving cultures have been selected so that they have made provisions for the protection and preservation of the old.

Mankind has managed to exploit this phenomenon through both the agricultural and even the industrial revolutions. We are the first or second lifetime/generation to not utilize our elders in this way. The abolition of the extended family and it's replacement by the nuclear family, or even the single parent, is the single greatest social change we have inflicted on ourselves as a species since we gave up nomadism for farming. Look around you, the results are everywhere.

Wouldn't it be ironic if the single nuclear family suburban home we worked so hard to create was gradually creating individuals incapable of
surviving as a contributing part of society? The urban dysfunctional family and the social breakdown in our cities is just a preview of what's to come. They just got to first, where the rest of us are heading.