What are the weaknesses of the United States?

The US economy seems to be in great shape: growth remains strong, the unemployment rate is very low. But we can identify a number of weaknesses in the United States: Obviously, the social model where growth benefits only a minority is not sustainable; The chronic shortfall of savings leads to continuous accumulation of external debt, which may pose a financing problem even with the dollar’s reserve currency role; The model with intense growth in fossil energies cannot be maintained in the long term; The very expansionary monetary policy is starting to give rise to financial imbalances: excessive rise in real estate prices, excessive valuation of new-technology companies’ shares.