> Except people continue to move to cities outside the U.S.People also continue to move to cities in the United States. Some of those cities have more people leave than come, but people are still moving there.
What would be more interesting is seeing how the share of the population living in large cities has changed over time in the USA and abroad. On balance is it growing, shrinking, or staying the same?
In my country, cities are still seeing growth, but since 2010 a larger and growing share of the population are now living smaller communities, especially those with fewer than 30,000 people. I don't know if it is fair to call that an exodus as the cities haven't seen any real population decline (overall population is growing), but there does seem to be a change in preference.
> At least in the U.S. suburbs are almost entirely subsidized by their core cities.
More often, the core city invests in the suburbs, namely to see a flow of workers from those suburbs come into the city, increasing productivity.
Those who call it a subsidy hypothesize that if the city put up a wall, the suburbs would become unsustainable and the people would then move into the city centre, after which nothing would change for the city except the resources would stay within the city limits. But that is not a foregone conclusion. More likely the people would stay put, giving rise to economic opportunity in the suburbs. The work they were doing in the city is going to go somewhere.
Of course, if that were to happen, both the city and the suburbs would be worse off. Which is why the city is more than happy to invest in the suburbs.