I don't think so; it will surely get huge, but it will never be going to be replaced with the dollar.
If it is by any chance, that will cause a lot of confusion in people.
For example, you're buying something, and the seller says it costs you 1Dollar, that's normal. When bitcoin replaces the dollar and he converts that 1dollar to Bitcoin every hour the price changes? And people will surely have no idea how much it exactly costs in their currency, either the seller has to convert it to the USD too.
Well, maybe in the future we do not need any cash or real money instead we are using a card or some kind of verification for the owner. And bitcoin is not yet perfect, i mean it will takes years and decades for someone to discover a new ways for it to completely work and usable for everyone. anyway, i'm just talking about the future you know.