The problem is: what will replace it? The Chinese yuan? Absolutely not, it's not a fair currency, and the Chinese economy is actually doing worse than the US economy anyway. The fucking Rupee? Lmao. The Euro? No. Again, the European economy is even weaker than the US economy. The Ruble? Absolutely fucking not.
There's not really any alternative out there. It's not really that the dollar is weakening, just that the global economy is in the shitter.
What is more realistic is not a grand USD collapse like /pol/niggers would have you believe, but a broad diversification of funds, where the USD becomes a "first among equals." Instead of companies keeping 90 or 100 percent of their holdings in USD, it will be something like 60/20/10/10 USD/Euro/GBP/JPY.