The only thing governments can control is the centralized ecosystem around Bitcoin, not Bitcoin itself.
They have the ability to subject businesses to their regulations where data exchange is mandatory in order to remain compliant, and this might already be the case without people even knowing. I'm fairly sure that at one point governments will come out of hiding and penalize those who refrained from paying their taxes and whatnot.
People still put a lot of faith in Bitcoin's "anonymous" nature, while there is no such a thing as anonymity at all when you use centralized services. One day even the small fishes will pay the price for it when the amounts they initially didn't pay tax over added up to a significant enough amount years later.