Bitcoin still exists even without fiat, Satoshi Nakamoto created bitcoin not to replace fiat, the use of bitcoin can be an asset in the future with bitcoin can be exchanged for gold not necessarily with fiat so bitcoin does not depend on fiat.
So true. Bitcoin will continue to exist without fiat. In the future I think fiat will be useless. Technology is advancing, people will get used to owning digital currency because it is more flexible, secure, and more profitable to store it.
I disagree, and I think it will not happen, if there's a currency that will replace fiat, it should not be bitcoin or any crypto since the government has to protect their own interest and they can make digital money, in fact, there is already a country that has started to create their own digital money.
China bans bitcoin and crypto in general because they have their own digital money.
https://www.wsj.com/articles/china-creates-its-own-digital-currency-a-first-for-major-economy-11617634118