If one day most of countries in the world ban BTC, will someone with a lot of money spend million or even billion of dollars to establish a whole country. In this country, you will exchange with BTC and other crypto. Will you leave your coutry and move to this 'wonderland'?
I think if you look at Japan, they already legalized it, so it makes bitcoin a legal tender together with their official currency, which is Yen. So they already started this tsunami, and so the scenario who have describe is somewhat already happening. As far as moving in this country, I think I wouldn't for now, because I don't have enough bitcoin to begin with. But for others you have lots of coins, then probably they will think of moving in this country because crypto is accepted. In Japan though, you have the language barrier and the cost of living is very high. So its unlikely I'm going to move there and start a new life.