> I agree that American society doesn't need any one particular city, but we do need a healthy ecosystem of urban areas. Do we? I'm happy to assume the benefi

> I agree that American society doesn't need any one particular city, but we do need a healthy ecosystem of urban areas. Do we? I'm happy to assume the benefit of a couple of finance-urban-centers, but it's unclear that there's a huge benefit from having finance, art, and fashion in NYC. If fashion and art were elsewhere, NYC would be significantly smaller, but would we be worse off? My point is that the big urban areas in the US contain aggregates that may not be particularly synergistic. If they're not, then its the "lower-tier" cities that are actually important, and that we happen to co-located many of them.