The marginal cost over time of Bitcoin shows an ever increasing percent being energy costs.  This means sha256d will likely be commoditized.  There is no Chinese monopoly after that happens.  Of course, China being the top producers of Bitcoin isn't even a Bitcoin problem in the first place.  It's a symptom of China controlling manufacturing for everything on earth as corporations use their slaves for global labor arbitrage.

This problem will also cease to exist either through tariffs or war.  US has already placed huge tariffs on China steel.  Next, every country will place huge tariffs on everything else coming out of China.