Op bitcoin is not competing with any country financial institution. And not also planning to take over a country economy, what bitcoin is doing is to create decentralized exchange system. And in the process of using bitcoin, any country that like to use bitcoin has their official currency can do. And it is not compulsory or mandatory that for everyone to use it. Like what happened in El Salvador is their personal decision and not others. Every government has their own policy that regulate the activities of the citizens. Like my country the government collaborate with the financial institution and ban bitcoin but the citizens are still using it very effectively with the fiat currency they are co-existing in the country.
I don't think bitcoin is going to take over the Fiat currencies and becomes the world currency,.
Well bitcoin as a decentralized payment alternative for everyone who likes it and more precisely on investment will not take over fiat instead and I don't think this is possible anyhow every government will definitely defend their fiat currency until whenever especially with a new economy of course they will not change with bitcoin as their main tool.
Even recently the government will launch a CBDC which is still in the development stage but this is based on their fiat so it will not depend on bitcoin and obviously the government certainly wants to compete in its digital currency, it's just that they want to control what has been made like CBDC.
I think you are right, bitcoin will still be an alternative while fiat will still be widely used throughout the world as its economic cycle.