This map shows national output (GDP) per person in different nations. The leaders seem to be financial centers (Luxembourg, Switzerland, Singapore) and oil and gas producers (Qatar, Brunei, United Arab Emirates and maybe Norway).
The USA is both a financial and energy-producing center, ranking eighth behind those seven nations, but way ahead of Russia and China.
While China’s overall economy is thought to be larger than the American economy, that doesn’t mean that the average Chinese person is rich.
Of course GDP per person is not the whole story, either. How the average person does depends on how wealth is distributed. What the GDP figure shows is how potentially well off the individual person is.