I think that the largest central banks of the world will not support Bitcoin as a reserve world currency. This is due to the high concentration of bitcoins in individual hands, mainly in China. If the majority of bitcoins were owned by the Fed, then bitcoin would become a world currency.
And then the crypto currencies would end up being a centralized currency. Then why would we be using crypto currencies any more? The whole point of crypto currencies were to bring a decentralized currency with no central authority at all. Once the network becomes centralized, we will end up losing our financial freedom. There would once again be no difference between fiat currency and crypto currency.