You really need go out more. You probably have no clue about how life is in other countries.
Man, I work with oil and gas exploration world-wide. I've seen as much as you can imagine, and more!

Why the dollar?
Because you can use the dollars almost everywhere in the world.
There are countries where you can get stuff cheaper and faster is you pay in dollars that in the national currency.
..and that's usually the most corrupt countries.
The countries we should help!
Because the dollars is backed by something , the us army. And with that behind it , it doesn't need anything else not gold not oil nothing.
In order for the dollar to fail the us must first lose it's military supremacy.
That's a very good reason for not supporting dollar, as it works the other way as well. The OPEC countries and Russia and China all knows that. It's only a matter of time before they find a good alternative, and cryptocoins might be a good source of inspiration for a global standard in such way that a single country can't manipulate out of debt by use of inflation.