It will not happen soon but there is of course a chance that it will be possible because you also see that Bitcoin is getting more used and more acceptable so that is nice
I think that's not a criteria on why bitcoin would replace dollar.
Governments don't want something that is uncontrollable. It's either they kill it or acquire it. Same as in bitcoin, It will only replace dollar if it is under the control of the government, probably a centralized one.
Honestly, we need to be realistic so we will know the real answer. Bitcoin in any way cannot replace Dollar because that currency is too powerful and I even doubt if we can replace a weak currency. The thing is, we do not belong to their level since we are decentralized while every countries currency has their own government to protect and to improve theirs.
I agree with what you're saying and to think that the Bitcoin will replace is weird if you understand me. A currency like the Bitcoin is not strong and used enough around the to do something like this. But we live in crazy world so you never know what might happen.