A lot of these subsidies (both in the US and China) are implicit. Chinese state rail networks operate at cost, allowing cheap transportation of materials and labor. American borrowing is heavily subsidized through the Fed Credit Window, which keeps rates in the low single digits while corporate bonds and consumer loans can be 2x-30x as high. Both countries cut corners on environmental enforcement and subsidize waste management. Both countries subsidize education and incentive R&D through their university systems.

The real benefit BYD enjoys - even above its Chinese peers - is vertical integration. They own everything from mining interests to technology patents to dealerships. This is a deliberate consequence of Chinese trade policy, which requires foreign investors to partner with Chinese nationals in order to own and operate capital. Consequently, Berkshire Hathaway - a large early investor in BYD - cannot dictate Chinese vehicle manufacturing policy from a private office in Omaha. Chinese locals benefit from the innovation, the domestic capital, the experienced labor force (which can migrate to local competitors), and the increased economic activity it produces.

China is insourcing it's wealth aggregation, which has a cyclical compound benefit over time.