I think the government is going to tax BTC as a commodity, which will insure it can't be a unit-of-account because legal tender is not taxed on VAT and capital gains. And then merge Bitcoin into some digital fiat plan...
I think you are out of your mind if you believe any such government-bankster hijacking of Bitcoin will be even remotely successful or tolerated by the cryptocurrency community.
World governments will have no more success taxing Bitcoin than the US government has had stopping the spread of piracy or winning the insane war on drugs.
And proper decentralized exchanges are coming sooner than you think.
Decentralized exchange won't help you. Because your IP address is still visible to the government, and Tor+VPN can't help you.
And the block chain is fully traceable and the available mixers won't really help you.
And CoinJoin is DOS-attackable in decentralized mode.
Sorry I speak the facts.
Eventually it will hit you like a brick. Then you will realize what the real future of Bitcoin is and that is going to be depressing realization for you.
I am not happy about, which is why I have been investigating potential solutions.