But how are populations developing? When people follow the money, GDP per capita evens out, maybe to the point of overcompensation given enough mobility and optimism to "make it there". Just look at how real estate prices are not matching the distribution of GDP per capita at all: real estate is less mobile than people.

(Edit: and yes, there surely are also some economic hotspots within the Midwest, some of those states are huge and have plenty of room to have their own internal concentration patterns)

Back to real estate, which brings us back to Germany, where rising real estate prices (both owned and rented) have increasingly been on people's minds recently: the solution cannot be just rent regulation or construction deregulation, it has to go to the root, find was to Conner concentration, to make the backwaters more economically viable, where housing prices ar not rising but in free fall.