Imagine the damage to any economy that adopted bitcoin as its currency, it would be hugely squeezed.

Just because there are free borders doesn't mean everyone wants to move, for example the EU has freedom of movement and while there is large scale immigration that is not the same as mass movements of people.  Mostly people stay in the area they were born / country of birth.

You'll be waiting a long time - the US has the most dynamic economy in the World and the greatest people so realistically it aint ever going to happen.

I am amazed there are some many phrases to get used to!