If the US economy collapses, all economies in the world will collapse, just as the United States does not need its currency linked to gold to be the global reference, but will impose it in other ways.
This is something that those that wish for the US dominance over the economy to end do not understand, the dollar is so dominant around the world that its collapse will mean the collapse of the whole economy.
This is why even if the political enemies of the US would like to see the demise of the dollar they cannot really take reckless actions against it as they will suffer the consequences as well, this is also why the dollar still maintains its supremacy over all other currencies, but as time passes and the economic conditions worsen even more as inflation keeps getting higher then the demise of the US dollar would be inevitable anyway.