This idea has a very low possibility since there is a flaw with the use of bitcoins. What I'm saying is that we need electricity, a device and an internet connection to use and there are still remote places in the world. Imagine in a tropical island for vacation, you are really thirsty and there is no reception, how can you pay for your drinks in Bitcoin? It's not impossible for bitcoin to be the main currency but my point is that this will still be a long way ahead.