Since bitcoin and other digital currencies are such a game changer for the traditional economics systems, could there be any government policies that can be devastating to this new market? and even if governments in North America or Europe might not be able to do such things, how about policies from other more centralized countries that could bring the same effect?
The most probable thing I can see for governments to keep hold of bitcoin being used is to diminish its usefulness, meaning governments will try to sanction companies that conduct transactions using bitcoin thus indirectly affecting the whole bitcoin ecosystem because if people can no longer use it the way they use fiat then the demand will surely suffer.