Per capita GDP is one thing, a lot more important is per capita income. Those are two very different things, particularly when you're talking about China - a country with a billion extremely poor people, and a lot of mega corporations that the state has blessed with near monopolies. What you want to know, is: how much money are the people of China keeping out of that huge economy.

Per capita income in the US is closer to $40k, and in China it's closer to $3,600 to $4k. In 1990, it was closer to $350 to $450 range (IMF).

The focus always goes to China's per capita GDP, but it's a very misleading way to measure economic parity. People get upset about America's wealth inequality - China's wealth inequality is several orders of magnitude worse.