I think the fact that you need about 50 years to save up for a down payment for a modest home and a couple with two jobs can barely feed themselves, let alone children, might have something to do it.

I once saw a documentary about a single mother in India who, through relatively simple manual labour - I can't remember what exactly - bought a small plot of land and was able to pay some people from the area to build her family a hut there.

Now imagine a single mum working as, say, a hairdresser in the West, trying to buy any plot of land and then not being government-regulated to absolute hell and back trying to build even a shed on it.