Bitcoin is just an asset that has some interesting traits, that make it more attractive to some people vs. other assets. Other assets will still exist. Other monies will probably exist too - they’ll have some benefits over Bitcoin in some use cases.

I don’t see why governments wouldn’t tax Bitcoin income and transactions the same way as fiat income and transactions. Me paying someone a hundred dollar bill is even less taxable than Bitcoin.

Obviously everything will sound dystopian if you take it to the extreme.