The other candidate was the current finance minister. After over a year of hyperinflation you'd have to have a lot of faith to go with the guy that hasn't been able to deal with the issue while in power.
Oh yeah, don't get me wrong, he's going to make things so much worse. But if you're going to put a candidate forward in this environment, going with the guy who was literally in charge instead of a clear left alternative seems bad, strategically.
Another: This guy is so cartoonishly fucked up that he can't not break the country (/system), meaning someone else will have to fix it once he's good n' [REDACTED].
Does the US even want Argentina to do this? Argentina is such a black hole economically and with so many different creditors already, that trying to integrate Argentina any more into the American Orbit risks destabilizing the whole thing.
There's a huge movement in the direction of dedollarisation in the global South. The state department would definitely be happy to see a country go into the other direction. Plus there's a whole bunch of state assets that are probably going to go on a fire sale, so Argentina can look forward to being effectively owned by Blackrock for the next century or so.