Does anyone agree or disagree with this presumption of mine?
Of course I disagree with it, otherwise I wouldn't own any Bitcoin. 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.
Add to that the west's unwillingness to engage in bitcoin chip manufacturing as chip manufacturing is one area where the Chinese don't really have that much of an edge in terms of labor, lithography being a highly-automated/robotic process. Plus they don't have an edge in things like 14nm-fabrication plants.
Even in mainstream consumer chips, that have economies of scale, companies like intel have no problem preserving their manufacturing advantage despite their fabs being located in the western world.
https://en.wikipedia.org/wiki/List_of_semiconductor_fabrication_plants