Many states have already legalized the crypto currency, but made it property, not a means of payment. But this did not affect the work of bitcoin. Difficulties in working with crypto-currencies arise only in those countries that have banned the use of crypto currency.
Yeah, a lot of states have legalized it for now and some are simply just quiet about it and I believe their idea of legalization would bring about some form of regulations and then when it comes to making transactions with the use of fiat, there would always be a need for fiat, and that certainly should make it not a threat to the government.
Even when we start hitting the point of real life usage, some of these tools will have a way of sticking with regulatory policies and comply and in that case, being a threat to the government will really not be a problem. If it is a huge threat to the government, we all know the government will frustrate and jeopardize everything.