To put in dummy terms sweetie, there was a world before the USD took centre stage, there'd be a world after the USD has departed from the center stage too. Just look at UK & France today. Last century this time they were the reigning super powers of the world with the US being one among the other lesser powers like Japan Italy & fallen ones who'd rise in less than 2 decades like Germany & USSR .
Hence the question you really ought to be asking yourself is when not if, sweetie? But if you knew that much you wouldn't be where you are & what you are, would you now?