Since economies are deeply interconnected it is clear that it is in nobody's interest to allow the US economy to collapse.
The problem of bimetallism (silver/gold) or just gold, is that they are scarce and not suitable to produce enough circulating currency for everyone, so a replacement seemed fair.
But fossil fuels are an environmental liability. Maybe the future is in some crypto-like thing.
The threat of the US economy collapsing is plenty enough reason to strike new deals to sustain its currency.