I don't think so, maybe the the goverment won't agree that bitcoin will replace dollar because first of all bitcoin was not created by the government. We can't say when bitcoin can consider a real money because we can only earn it in the internet. Maybe one day bitcoin can replace dollar someday.
It isn't going to happen I really doubt that bitcoin will ever replace dollar very soon. We know that government is against the concept of bitcoin because it is decentralized and they can't have the power to control it. So I know that government is trying to adopt this idea but not the whole thing.
Yes, that is the thing why government will not accept bitcoin as a currency. The transactions of bitcoins are really anonymous that is why of it will be implemented as a currency of one country, it will be used on many illegal activities and transactions. And it will be so hard getting taxes on the people, it may lead to the failure of the government. It will stay as a digital currency accepted by stores and exchangers.