The idea of the USD petrodollar was conjured up after WWII and implemented in the late 60s and early 70s during Nixon's presidency as mostly a quest for power; the US could offload some of its inflation and simultaneously increase demand for the US dollar. The US is the largest oil producer in the world, the oil agreement gave them (Saudi Arabia) military protection and arms in exchange for denomination of oil sales in USD. The point of the agreement was to offload some of the US economic inflation as those dollars never entered into the US economy, but most importantly to gain economic power over the one resource that rules them all.

Most countries continue to buy oil in USD because of the protection (well used too in a way) it affords against larger non-allied countries, pirates and other rogue states. Civilization and the military need oil; most importantly, the military. As long as oil is priced in USD, the US government can continuing printing dollars to pay for it and to maintain reserve currency status. If the oil agreement folds, the US can continue printing money, but the economy will suffer. This is one of the ways the US became so big so quickly.

The US looks like its suffering from Dutch Disease with its export being currency and not natural resources. Once the currency well dries up, banks will lose some power and the US will begin a multi-decade race to once again ramp up manufacturing (Made in America TM) to try to mitigate the loss. Problem with this will be that because of the eventual USD decoupling, it will be a race to the bottom.

This is where I believe Bitcoin comes in. SDRs under the guidance of the IMF are nothing new; essentially, a world currency basket to hedge currency volatility. Dump all your country's debt into an SDR and well, you know the rest.