The two biggest holders of the U.S. debt are Japan and China. Japan is not an independent state, so it is effectively out of the equation (whoever begs to differ). China is the largest trading partner of the U.S., so it is very unlikely that it will drop its U.S. treasury holdings all of a sudden. In a sense, it can be said that right now the U.S. feeds on China, but how long will it last?
The US has been pushing SDRs through the IMF for some time now. SDRs came out of the Bretton-Woods System and where created as a fail safe for an expected USD shortfall in the 70s.
Interstingly, the US wants to bring China on board. The Chinese want no part as they stand to lose out because of all the US debt they hold. It's becoming clearer that the US cannot support the reserve status it has anymore, but is unwilling to relinquish the power the position provides. The rest of the World is becoming wise to the US antics.
I give it 15-20 years for full transition to something different. With things like BTC starting up in the late 2000s, I fully expect the US has been planning for the eventual end for a solid 10 years prior, maybe 20. Policy shifts take a lot of time, especially given the current one is ~100 years old.
The US may be feeding off of everyone else (I agree with you), but we have a large military. Might always makes it right no matter what. There is no morality in power. It is amoral by birthright. China will have no choice but to submit given the current economic devastation of its allies i.e. Russia/N. Korea/Pakistan (unless this changes).
Look for increasing manufacturing on the US home front and a larger return to made in America. The era of the US exporting dollars for a living is slowly grinding to a halt. The idea would be for the US to start selling China stuff and control the fiscal monetary unit used to trade as well. China will be a US-debt bagholder with the US no longer paying off "those" debts.