Bitcoin is not as popular as the US Dollar. US Dollar has been there for a long time so people have talked about it ever since. Before most of us were born, people already know about US Dollar and it has more value than most currencies.
Bitcoin, on the other hand, is relatively new. As we approach a more and more digital world, Bitcoin is also arising. People are starting to talk about Bitcoin but I don't think it will come to the point that Bitcoin is more popular than US Dollars any time soon. But it will, eventually.
Yea, the bitcoin is already some time in the game but the Dollar is way longer in the game, more used and also bigger right now, due to this I think the dollar will win it easy from the bitcoin on this moment.
I also think that the bitcoin market is depending on the dollar, so if the dollar will fall the bitcoin will drop too, I think that is already saying enough about this.