governments will find a way to get their tax hands on it eventually. The only avenue they have is legislation because they cant attack the network and stop it.
The real question is how many people would actually no trade BTC even if the government said "you can't buy or sell BTC in this country"
most people currently in BTC would just load up a VPN and keep on trucking like normal. Many use BTC for that exact reason.
I think a number of states will definitely go after BTC through legislation, and it is likely the more volatile states. The Robert Mugabe's of the World definitely don't want their citizens to have other options. Developed nations will likely look more toward regulation. Hasn't Thailand already declared it illegal?