They are being built, just sort this list by % change and look at population over the past few decades: https://en.wikipedia.org/wiki/Metropolitan_statistical_

They are being built, just sort this list by % change and look at population over the past few decades: https://en.wikipedia.org/wiki/Metropolitan_statistical_area https://en.wikipedia.org/wiki/Metropolitan_statistical_area A bunch of places towards the top of the list (not just a few) have doubled or more in population over the past 30 years. It is just that in the US people have a death wish and often flock to places like Phoenix and Las Vegas and San Bernardino rather than some place sensible and organize cities into the same endless sprawl everywhere.