US nominal GDP is becoming increasingly divorced from reality. It used to increase like $0.5B a year now it's doing $2B a year. Has the US undergone a technological revolution to warrant this increase in GDP? It hasn't. It's simply inflation, debt, interest rates.
Simply put, US GDP seems like a bubble. 90% of American workers do the exact same job as everyone else in the developing world with the exception of 10% of Americans who work in tech companies like Google, FB, Microsoft, Apple, Intel, Nvidia, Qualcomm, Tesla, and research institutions which is what really props up US GDP and allows the American barber to earn (and contribute to US GDP) 10x the barber in any other country while doing the same exact job.
It would be sustainable for US if it weren't for China challenging their technological dominance.