And in the end, the US could just end up winning because its opponents simply don’t know how fragile it actually is, and made all the wrong decisions instead of sticking together and launch a cohesive assault against the dollar.
I don't think there's a situation where the US "wins" because that's not really how it's happened in the past; the contender states are rising in opposition to the US as they are geopolitically bound to do. It wouldn't really matter if the contender states were capitalist or communist. Germany, Japan, and the United States rose as contender states to oppose the British Empire's much stronger hegemon and none of them were communist and the global currencies were at that point either the sterling or the gold standard, both of which the British Empire more-or-less controlled. Even in the absolute worst case scenario for the anti-hegemon and the absolute best case for the US, we're not looking at the US empire lasting past this century. Let's assume the worst happens and China's government topples and a capitalist one is instituted instead - they'd still be contending for the top spot in the arena of generating profit. And even as communists, China is caught up in the same global conditions as everybody else, the same generally lowering rate of profit as per the TRPF, the same development of neo-colonies, the same increasing difficulty to acquire resources as all the easy-to-access spots are taken up, etc.
I strongly dislike any theory which relies on a person or group of people having to "make the right choice" beyond that which their immediate interests lie. One of the many reasons I like Marxism is that it doesn't at all rely on, say, a person or group of people suddenly growing a heart and betraying the bourgeoisie as a prerequisite for the workers to institute a dictatorship of the proletariat. In a similar vein, at the geopolitical level, it shouldn't matter what the people inside China or Russia or the US want to happen, it shouldn't rely on, say, the Chinese leadership being presented with either dedollarization (growing a heart) or maintaining the dollar (acting selfishly and against their long-term interests) and then either choice shapes the future of the human race. It might not be inevitable per se, climate change or rampant disease or an asteroid impact might still get us of course.
But if we're in a situation where the only way out of US empire supremacy is a particular national government making a choice that works against their interests in the short term (as dedollarization would be a painful process for China) then we are very probably fucked.
Essentially what I'm trying to say is that if the US "wins", and neoliberalism prevails for decades or centuries, then Marxism must definitionally be incorrect. We must have made an incorrect judgement about the viability of capitalism, perhaps the rate of profit does not in fact fall over time, and the theory is wrong. Until somebody points out that fatal flaw, then I don't see how Marxism can be wrong. QED, the US will not win.
this will actually make their soldiers more competent, then