in future im sure bitcoin will be stable at ~$500 (after mining ended)
more country will be use bitcoin, and bitcoin will be number 1 online payment
Why would a country use a system like Bitcoin? A country wants to control its currency and it's a normal thing to do that

It's not what the country wants to do (the state), it's what the people in that country willing to use in a form of currency.
it seems that people follow their government blindly, at least the majority, they think it's more secure to use fiat because regulated and shit like that, it's the primarily reason why bitcoin can not take off