Election promises rarely translate into reality, has he done it so far?
San Salvador uses Bitcoin alongside with their local currency plus the $ I think.
Exactly. Politicians usually lie to get the attention of voters. Argentina's President Javier Milei hasn't been able to keep up with his promise of abolishing the central bank and declare BTC as legal tender. Not even the dollarization of the Argentine economy (through the USD) has been accomplished. El Salvador might've been the first country to adopt BTC as legal tender, but it still uses the USD for day-to-day payments. I guess it's too early for countries to completely abandon the USD.
Rest assured that the time will come when the USD loses traction as the reserve currency of the world. Rising US national debt, and constant money printing (inflation) should lead us there faster than we've previously imagined. The real question would be: Which currency will replace the USD in the future?
USD will still be used. i don't think anyone can remove it as a major currency especially now that we have USDT and the rest of the stablecoins. El Salvador still uses USD along with BTC, if they start using Yuan, i bet the US officials will fly there for regime change.
eventually, everyone in the future will be using stablecoins and maybe the Euro, Rial, Ruble, Yuan, and Peso and all the rest of the currencies will have their stablecoin. but there will still be dominance for USD particularly in America.