They are trying, but the only thing they can do is adjust the way you receive Bitcoin. We have seen this through KYC and various exchanges tie this down when users. But sorry, Bitcoin really can not be adjusted. But I think someday Bitcoin will do this so that it can be accepted by the government, so that it can be widely used.
Governments can monitor their fiat channels since they have a very strict control over them but if at some point in the future people begin to accept bitcoin directly for all kind of products and services governments are going to have a huge problem not only regulating bitcoin but the rest of the economy as well since we will not need to follow their rules.