because bitcoin has not yet become taxable and the state with it is not considered and until it is perceived seriously, but it will not last long
I think there's a huge and very expensive process of tracing it, making the whole set of laws.
Bitcoin has not become a legal currency because not all countries, world bodies have accepted or recognized it. You write so much and how you fail to understand that this coin can not be controlled by anyone, nobody can manipulate it and most of all governments can not know who owns it or make you pay taxes.