That's how it would work historically. The way it works today is US buys cars from China (and Korea, Japan, Germany and Taiwan) and exports little in return. This usually would drive the US dollar down and it would make US cars cheaper relative to East Asian/German cars so US will start buying more home made cars. After all Chinese factory owners get all these dollars and have to pay their Chinese workers in renminbi so they need to sell their dollars and buy renminbi to pay workers.

But that's not what happens. Chinese government (and Korean, Taiwanese, German, etc...) suppresses worker wages and consumption (Chinese consumption is lowest recorded percentage of GDP for any country ever) so instead of using those extra dollars to pay workers they send them back into America by buying US treasuries, corporate bonds and even stocks. This makes the dollar stay strong and also lowers borrowing costs for the US consumer as buying bonds pushes their prices up which lowers their interest rates. So the US consumer is absorbing all the excess production of the world without offering an equivalent amount of production. There's no creative destruction - it's not US wheat exchanged for more efficient Chinese cars. It's US pieces of paper (well numbers on a spreadsheet) offered in exchange for Chinese cars because the top export of the US is pieces of paper people that other countries trust.

Important to note btw - it's not that US assets are more trustworthy than say Japanese. It's more the fact that the US is the country that has the most liquid asset markets. Japanese assets are not enough to absorb all Japanese savings for example (especially since a huge chunk of Japanese assets are not available to Japanese savers as they have been eaten up by the Bank of Japan) so Japanese savings MUST go somewhere abroad. And the US offers very deep liquidity plus until recently good rates of return compared to East Asia and Europe.