I came to see it as a social experiment, because what I learned, surprisingly, is that until about the 1950s,there was no society in the history of our species that supported large numbers of people living alone. Since then, living alone has become incredibly common, throughout the developed world. Wherever there is affluence, and a welfare state, people use their resources to get places of their own.

http://www.smithsonianmag.com/science-nature/Eric-Klinenberg-on-Going-Solo.html?device=android