The explanation that I'm finding more and more compelling is that this is because there's actual competition in China, whereas in the west conglomerates have been able to carve up the market into fiefdoms and feast, with increasing amounts of cash that they can funnel into dividends and buybacks.

From the NA vehicle POV it doesn't look healthy. Stocks of the major auto makers have done well this year, while product gets more and more expensive and limited. Barely seems possible to buy anything but a F150like anymore.

You could say that about the Chinese stock market in general. Neither the SSE Composite nor the Hang Seng correlate all that well with Chinese GDP growth.

Chinese companies are optimized to grow and build stuff. US companies are optimized to deliver returns to shareholders.