[sydd]

IMO the main issue are zoning laws and urbanization. You can find lots of articles about rural areas, small villages elsentially dieing out, while large cities just (try) to grow larger.

Also there is a shift from people living in families to living single or just with one person which is more inefficient and requires more space.

[Aerroon]

We're definitely in some kind of next stage of urbanization where people are moving into the big cities even from smaller ones. It's very noticeable in the former Soviet states, but I believe it also happens elsewhere.