for me i think 1 day will come all fiat currencies will be lost and only cryptocurrency will remain
What makes you think it will happen? with the fact that, some countries do not accept and prohibit bitcoin activity. I am just pessimistic this can happen. although currently, bitcoin is still unfamiliar to some people.
in past some people dream if bitcoin will change fiat and become mass payment. but now they complain about fee when they want to send their coins.in my opinion, now bitcoin not suitable to be a payment because fee problem. and a lot of government ban it like what you said