Milei was a long shot candidate and he was elected on the back of this one issue. Dollarizing the economy and the radical measures Milei ran on in that election have a very real risk of collapsing Argentina. But, the general feeling here from the people I know, so anecdotal of course, is that they would rather risk economic collapse than guarantee it.
Also you act as if America is some bastion of fiscal responsibility. Its position as the worlds largest economy guarantees that it can borrow at the best rates. The dollar being the worlds reserve currency ensures that it can’t devalue too quickly as there is built in massive demand just for normal trade.
So, it has large advantages that Argentina can only dream of. The hill Argentina needs to climb is far steeper than what the US has to contend with.