You cannot suspend the laws of cause and effect (even though that is what liberals think they can do every day)...

America reaches a tipping point

Kotkin describes the process of centralization, but not the likely results. Centralization means rigidity, less adaptability, slow growth, concentration of wealth and income, and probably even lower social mobility — as loss of regional autonomy means fewer opportunities outside the capital. And vs. other developed nations our social mobility is already low and inequality high (see here and here).