That can be said about any export. What if other countries don’t want it anymore? Well then you have to diversify. Looj at Russia or Venezuela and how oil prices affected them. That’s their “dollars”.

But if the USA is able to keep doing machinations around the world so that the dollar is demand for 200 years, eg by just making it the most stable currency, then their dollars and treasuries will literally be the thing that they trade for everything else. Like what if a bank goes insolvent... ok but what if it doesn’t, then everyone wants to use its money and credit.

The USA also lobbies for strong IP protections and international treaties because that’s another one of its exports.

Manufacturing and raw materials are actually less likely to remain a comparative advtantage than this artificially enforced stuff.