From what I have seen so far in this forum and other crypto platforms, most of us want fiat eliminated. But let us not forget that there are still situations whereby we can't use crypto except fiat like in rural places without computers or even internet facilities.
I think as of now, cryptocurrency still has no chance to overpower fiat. Still people believe on the capacity of bitcoin but dominating fiat would not be possible as of now. I think if that will happen, I would not be able to witness it because that will take too much time to take place. There are many factors to consider and a decade or two will not be enough.