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.
There are many more reasons why crypto should not replace fiat money. Just like our poor people, it is difficult for them especially when they are not earning enough to use, buy, mobile phones. It also includes those who have not completed their studies. I think it would only happen if everyone in our world had the same view, the same thought, the same thing, all the same and it didn't happen because the world needed balance! nor does it happen that fiat money can replace crypto!