greece nearly drug down the EU when theirs popped off,

Erh no! Don’t trust the sensationalist stories about the Euro collapsing for this or that reason. Those stories are always without merit, my guess is they serve a purpose for speculation or are just sensationalist stories.

USD is the cornerstone to the entire western financial system

What are you smoking? It doesn’t make a hoot of difference to the rest of the world to trade in another currency. But more likely than not, it won’t be a single currency replacing USD, it will be a basket of currencies where USD will probably be a part.