Some people will argue that it did indeed break the system and that it never ended, it only shifted into a less obvious manner. And as for the hypothetical selling off of the U.S. Gold reserve... Some people will argue that it's already done in order to supply China and others seeing as yearly production doesn't fill the yearly demand. The U.S. Dollar used to be backed by gold, then oil and now it's backed by the military. Fiat currencies worth stem from one thing and one thing only, confidence. Once people loose trust in the currency it's all downhill from there.