BTC was created with a new transaction system without a central authority. The BTC can be used in the future as the main currency that we gonna pay with. But what's gonna be the value of a main currency? What's the value of dollars or eur?
-Answer is: The dollar IS the value. The dollar doesn't cost anything. The dollar is the value.
If BTC is gonna be used in future, it not gonna cost anything, because the BTC is gonna be the value. It not gonna be like Bitcoin cost 50,000dollars... Bitcoin not gonna cost anything because Bitcoin IS the value. But that's probably not gonna happen. We not gonna pay with BTC but with stable coins like USDT...
Being optimistic isnt bad but dont consider for this thing to happen because it wouldnt happen even on my dreams on which Dollar or fiat in general would lost its value yet we know that as long government does exist
then it wont surely happen. Why not they could both co-exist to each other? We do have some options to take whether dealing with typical centralized fiat or dealing with decentralized things like crypto.
At least we do have a choice or option to take and we shouldnt really bother ourselves or thinking off that there would be some replacement thing that would happen.
Thats not gonna happen no matter what.