@KeetSeveral of the OPEC members are heavily vested in the current system. Saudi Arabia for instance. To ditch it would require a great amount of pain on their part as a result.
The US President has a firm cap on the time in office they can serve. Eight years is the legally mandated term(s) limit. For other countries, part of their calculus is that term limit. Would the pain to them and the rest of the world be worth it? The current answer is no.
I don't personally have a problem with nationalism. In my opinion, if you're not going to take care of your own people, you shouldn't be in a position of power over them.
The left/socialist/liberals have been diligently working to demonize the term nationalism. Every PC term is rolled out to silence opposition. Racist, bigot, hitler, etc. If you don't agree with them, then you are any and all of those terms. I find that strange since the National Socialist German Workers party aka Nazis were socialist. Stranger still that revisionist history now brands them as part of the far right.
In my opinion, attempting to form one government from countries with a long standing sense of nationalist pride/history is/was doomed to fail. You cannot be a Spanaird, Greek, German, etc if you are an EU citizen. It is the same choice forced upon Native Americans. We can choose to be part of the US, or we can bury our collective heads on the reservation. To date, that hasn't worked out very well for us.
As for the dollar eventually losing all value, as stated before, it's inevitable. The longest standing contiguous currency in the world today is the British Pound. Even it has undergone many changes over the last couple of hundred years. Every other currency has changed in all but name. It too will eventually die off.
Regarding the US dollar, I've taken many lessons learned from countries that have fallen and risen economically in the last fifty years. Brazil, Argentina, Ukraine and every other former Soviet state, all have lessons to teach regarding how to survive and thrive in such a collapse. I've planned for myself and family accordingly so:
Scary thought. not?
My answer is not so much.