Currently, there are many usd-based stablecoins such as, usdt, busd, usdc and maybe many others. To be honest, I used to think that crypto would completely eliminate the usd's dominance of the world economy but I was wrong, it turns out that usd is now evolving to crypto (stablecoins). What do you think, whether in the future bitcoin or other crypto can replace the role of currency in each country and leave fiat currencies such as usd, euro, yuan and others.
You are right that there are many types of stablecoins out there already like the ones you said.
To answer your question into whether crypto will replace the role of fiat currency, try to answer this one first.
- How much of the world's population right now have access into crypto?
If you have an answer to that one then you will know the answer into whether it will replace fiat. You are asking this question because you yourself are involved into crypto for a long time and to think that it will replace fiat currency? A currency that has been there for just 12 years will replace it? Not all of the people worldwide have access into crypto and in fact, there are a portion of people in the world that has no access to smartphones or whatever technology that it needs to access cryptocurrency.
On the other hand, crypto and fiat can exists at the same time so why the thinking of "Bitcoin will replace fiat in the future" and the like? I don't get the idea with this TBH because at first place, crypto isn't created to replace fiat.