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.
In my own opinion, government will not eliminate cryptocurrency immediately since there are a lot of people today in the market who are investing cryptocurrency and that is the reason why it will be very useful for different people to have more income monthly but fiat will still be very important for different people.
It will never be happened, since there are still 3rd world country's which means not yet using internet technolgy where as they are still using traditional transaction through fiat. And I guess, the crypto will be evolved, but not totally being the main currency in the future, it will still an alts, and more be countries will be using it.