I don't have any idea to give a statement if there is someone who say bitcoin will be a global currency. In one side, I'll be very charmed to see that's happen because I'll be someone who support and part of user who started it from the bottom. But in other side, this thing is really difficult to happen, I mean when there is many countries who use bitcoin and give direction to their citizen to use bitcoin and they will make a decision to burn their currency, yeah it won't be happen in my humble opinion.
But I'll bet there is no project who will be able to overtake the popularity or the price of bitcoin in the future. Many people out there just still believe to it and even they are thinking that the new project is scam and most of them is have centralized system which is mean it is far when we talk cryptocurrency. Because we use cryptocurrency we don't talk about the function of the project itself but the price factor will always be considered by the user.
the possibility of bitcoin will become a global currency is certainly there, although it may be a small possibility and it takes a very long time. because the amount of supply is only about 21 million and with the current price will not be sufficient enough to become a global currency. except for a few decades going forward after the price of bitcoin goes up tens of x fold, we'll see and I myself hope that bitcoin will become a global currency.