I dont think so that the Bitcoin will replace the dollar and that is because there are now a lot of people that is waiting for a price increase and not many people dont even know what Bitcoin is so that have to change.
And you can not pay everywhere with Bitcoin so that is also a big problem of the currency.
In the future I think but not soon, that future I am talking is maybe around 20 to 30 years from now, with the continuous support of bitcoins that can be possible and we should rip the fruits of our investment if that will happen as the price will increase substantially.
I don't think that will be possible even in future. after 30 ro 40 years.. it can only be possible if bitcoin can be printed like currency notes and can be spent like real money. which is honestly not being done. we can't predict about after 20 , 30 days even we don't know what will happen with bitcoin next week or next month..