With America still America, it would have even been impossible for Euro to take over the USD even if they had not had this plan of England breaking out. The united states has held so much power that they will do everything possible to ensure that their usd does not loose relevance, and we see how they have tried everything possible to even make bitcoin usage impossible, but the only luck that bitcoin had and why they have not been successful is that bitcoin was built on a decentralized platform.
All these other fiat currencies are all operating through a centralized system, which makes it very easy for their government to manipulate their way and ensure that euro does not see the light of the day and it will even become very tight for euro now that there is cryptocurrency.
And funnily enough, all of that power and might is held in the throes of debt. Every time the US flexes, it reminds me of that kid from school who splashed his money around, looking glam and impressing the girls, and suddenly looking so cool and full of personality, helped on by the illusion of power (money).
And then all the while, his credit card's bank is happy with every swipe, cause they want to own him, his home, his land, his credit.
Now imagine who smiles every time Uncle Sam and the Fed splash out with them dollars.
And then, imagine why the worry when Bitcoin entered the scene.