KAG
Couple of points:
First, those are Purchasing Power Parity, not real currency at current exchange rates. It would look more in US favor if not PPP.
Second, a fairer comparison is per capita numbers-American looks much better on that basis. The EU, on a per capita basis has a much lower standard of living and forget about China.
However, I agree the US is falling fast. Our infrastructure is way out-of-date, our political system is under stress and the dollar is down. Until the country makes some hard decisions, mostly on entitlement programs, taxes and a sustainable direction, it will continue a troubled path.
GF