I wonder if the concentration of wealth in a few also concentrates effective political control in the same few. Thus a narrower national political agenda can be pursued; that is, the agenda that further concentrates power and wealth in the few including via foreign policy.
If that were so, then the US would be heading away from popular democracy and toward some form of corporate oligarchy, hopefully with democratic characteristics.
Such a drift would reduce the US long-term influence in the broader global contest of ideas, kind of like how capitalism/democracy/socialism with Chinese characteristics only affords the Chinese limited international political legitimacy.