I also believe that it can replace in the future because the cryptocurrency today is in the mainstream and even countries are banning bitcoins because they are scared that more people will turn their focus on the cryptocurrency more than working on the corporate world.
I think Bitcoin will be never replace dollar because bitcoin is a digital currency and it is use for online work in worldwide, but dollar is a real currency and it is use hand by hand and that's why everyone can easily buy and sell from it, so there is a main difference between dollar and bitcoin, but the main point is that bitcoin is more valuable than dollar and everybody wants earn bitcoin for best future,