IMO it is also worth considering the rising Chinese middle class which is projected to be about 634 million, about twice the current total population of the United States, by 2025 or so. This is a lot of buying power but also a big problem if the Chinese economy doesn't grow as forcasted, they can't find jobs, and start revolting.
China is also liberalizing, cutting down on corruption and moving towards greater freedoms for the people as a whole. They are still far from perfect, but Jinping is a reformer from my layman's point of view.
All currencies are manipulated, and the West will not give up control of the international financial system easily. QE is one thing, but there are several more arcane methods by which this is done, few of which I totally understand. The price of a gold is a prime example. This is done in cahoots with the other central banks. It's far from a free market economy and a lot of China's moves have been towards devaluing their currency to maintain their export market which is dominated by trade with the US.
I don't see it happening in 10 years, but the US dollar and economy is in for some rough times unless we can get our spending under control. If the trend continues, I'm taking even odds on the loss of the USD as the world's currency within 30 years.