There's a number of ways it could play out, it depends on the decisions made by people in power. Trust in the USD system is deteriorating as it is becoming more clear that the debt will never stop growing. Any attempts to get spending under control will cause a global financial crisis, and requires the legislature to cooperate (not happening). Continuing to spend as we are is going to cause more inflation. Inflation will cause loss of trust, especially abroad. BRICS will look for alternatives, and will hopefully settle on Bitcoin eventually. Once a major trade deal is made in Bitcoin (probably for oil) that's the beginning of the end for the USD as WRC.

Might not happen that way, and I think it depends just as much on what BRICS does as it does on what the US and Europe does. The status quo will continue as long as it is beneficial for the majority of the major players. The Fed has bought some time with the interest rate moves in the last year, but it is stressing the system and the interest will come due and cause problems over time, or something could break and force a change in policy. Who knows. All I know is the system is fucked and the only thing holding it together is faith which I will not put my trust in.