[Dylan16807]

I'll put it this way. If 10-20 popular cities try to outbuild their population growth with a cap of 16 million people each, at least some of them will succeed. Three quarters of the US population isn't going to move into 10-20 cities.

The only way that general idea fails is if the demand concentrates so strongly into a couple megacities that we don't even have 10-20 non-obsolete cities left. That seems unlikely to me.