> We have so much land all around this country and no one is using it.
As the old real estate mantra goes, "Location, Location, Location!"
Of course you can buy a house with a yard and a large garage, but can you buy it on a regionally-adjusted salary and be reasonably close to a town and your workplace? Locality is still important for the vast majority of jobs, even in this age when the capability to telecommute is here.
I think the key contributor to this asymmetry is the scarcity of the human attention. People remember a handful of cities/towns which they associate with prosperity, despite the fact/possibility that far more areas are also prosperous. It's the same reason that a few dozen universities at the top of the rankings thrive, while perfectly decent schools just below them struggle to attract applicants.
Whether the issue at mind is red/blue state or rural/urban, Americans have become more risk-averse when it comes to moving to different regions.