US dollar will not go away or delisted from fiat currency but it is possible to lower the value in world bank because Yen makes more stronger its value than US dollar..now Yen are using around the globe likes chinas product we all know that no one place in this world is not using chinas made products.
US government has a huge debt with China actually it equivalent to the price of american soil or teritory for them to pay this debt.
This is one of the reason why US dollar is not strong currency compared to yen.
really once the US dollar will never die,
and China is very smart they can mambuat a variety of interesting products and in the interest of various countries in the world,
this is why the yen is in juxtaposed with the US dollar
all this because China's largest source of income is in products that are expended to various countries that make the yen price becomes very strong