The government might find a way to control bitcoin in the long run. You say how?
Well, by removing the privacy cloak on cryptocurrencies; making it mandatory for all exchanges to verify your data the same way banks do.
Thats all well and good for exchanges but what they can never stop is p2p transactions, it would be like the government trying to tax you everytime you gave a friend $10 in cash, won't work.
If they could match address with person, then it's no longer like cash. If they forced every exchange (and BTC accepting businesses) to comply with KYC policies and criminalise any p2p BTC/fiat exchanges, then any 2 people could still send btc to each other, but the moment you try to cash out or buy something officially, you'd have to be prepare to explain where did you get that bitcoins from.