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.
That's true not all countries are the same there will always place in every country where there is no internet access but people from this area accept fiat, if we take out fiat to them they have no means to get paid and pay for their product and services.
They can always co-exist we must never think of extinction of fiat it should be one of the options.