we've been through a lot of topics like this...
Bitcoin cannot replace fiat currency because fiat comes entirely from a country. currently, there are thousands of fiat currencies from all countries of the world. replace fiat means to replace a national currency. Bitcoin will continue to move alongside fiat.
it is not possible to replace FIAT, especially USD. To become the currency that has been agreed upon, then Bitcoin must be able to beat those who turn their backs on this giant currency. Moreover, if the government adopts a currency with a high level of transparency such as Bitcoin or altcoin, they will have problems in doing business. Money printing will be more sensitive because the data will be recorded on the blockchain and published.
let's stop being idealistic, and start being realistic about Bitcoin, FIAT and the rulers.