I am being imaginative, but can government intervene mining? or even replace tax with mining fees if bitcoin becomes the main stream of economy,m since bitcoin transactions are hard to tax?
Which government do you refer to?
In many countries like the United States or European Union Bitcoin is already regulated to some degree. Regarding Bitcoin becoming mainstream, this is unlikely to happen any time soon because it apparently means displacement of fiat currencies, but no government will ever agree to this. Why would they want to replace the currency which they can fully control with something they can't control?