The fact El Salvador accepted Bitcoin as a legal currency does not mean that other government across the world will accept it someday. The reality is that , the government will keep fighting bitcoin with all market strategy and strick regulations.
Reasons why they will keep fighting is not about the prosperity of the people majorly but about power and authority to control people. This is why they prefer the centralized system in order to keep the people poor so that they can run to their feet for daily bread, seek shelter and wait for other provision.
We all know that through Bitcoin, every one will be there own boss. No control or submission to any authority over your own belonging or money, the life threatening taxes will be done away with.
But as of now, no matter how popular Bitcoin becomes, it will keep facing the wrath of the angry government who need to keep people poor.
More also, before bitcoin will become used by everyone across the world as means of payment, most users hear must have grown white Bear,
I doubt the government will want to keep fighting bitcoin. What they will try to do is bring it under their control which would be almost impossible. Hence, right now all they are doing is pulling out policies and imposing absurd laws so they can at least indirectly control the whole network. The government cant help but accept crypto currencies eventually. Fighting it would only leave them behind on the field of financial tech development. The future is fiat and bitcoin/cryptocurrencies being used together. About the taxes part, even if bitcoin goes mainstream, you will still need to pay taxes. There is no escaping that.