You don't come out and say it, but your implication is that this is not possible.
It is not obvious to me that that is the case.
1. China is a low trust country. There is a deep culture of fraud and deceit. This will be a difficult thing to change, which I believe is a precondition to being a tier 1 super power.
2. People like to extend trends into the indefinite future, but macroeconomics is superstition at best. The stagnation of Japan caught just about everyone by surprise. I think there's at least a 30% chance this happens to China, based on some of the reports I've seen coming about of China related to debt and real estate.
I think there is a good chance for China to reach tier 1 status, but it doesn't seem like a foregone conclusion to me. Given this level of uncertainty, it seems reasonable that some powerful Americans might not want the US to go gentle into that good night.