Governments can't monitor many human to human transactions or not "know" how many tomatoes a farmer grows and sells seems to completely ignore the rapid growth of surveillance already happening and the exponential curve of AI in the present and imminent future.
Government assisted by AI can know pretty much whatever the fuck they want, and in some ways already do. Especially when you add in other incoming tech like the rapid development of drones etc.
Yeah you are right now a lot of the people are making profit from the bitcoin. It is the currency of the future and it will grow more and more than decreasing. No government will stop using bitcoin and it will not let bitcoin get down at any cost because it is the time for all of us to make bitcoin more popular so that the government will legalize bitcoin and they will increase the price more.