Well China's now the world's largest economy by PPP GDP [1] so it makes some kind of sense. I'm not sure how freely convertible the Yuan is though. [1] https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(PPP)
This is not based on GDP. A big part of the USD's stability has been based on an indirect oil backing. Going back to the 70s the US in which we offered substantial benefits to oil producing nations in exchange for little more than them only selling their oil in USD, and then investing excess revenues in US securities. The petrodollar in another word. This has numerous positive effects other than what I'm mentioning h…
Feel free to elaborate