Bitcoin will change the world, in some way it has already.
But it will never be the global cryptocurrency just because it is too slow and too resource intensive. If u look right now, only a small amount of humanity have invested in Bitcoins and some altcoins. Now think that the rest of the world are getting into it. Bitcoin cannot handle it. Maybe some other coin with an other technology can do it.
I think cryptocurrency at all will change the world definitely.