Haven't seen any communist places go to an anarcho capitalist system, so your comparisons don't say much. The mere fact that Milei won makes me want to find out if I can move to Argentina!
Our Constitution says that everyone in our country has the same rights as an Argentine, even if they are not. So you can get a national ID pretty easily, and in two years (which can take more time if you are living in Buenos Aires City, due to bureaucracy) you can become an Argentine. You must know too that it's impossible to lose the Argentine Nationality. Once an Argentine, never not-an-Argentine.
We are a country that's very open towards immigrants, as most of us are descendants of immigrants, mostly from Italy and Spain.
Governments usually have priorities and policies that artificially make something valuable - for example rocket scientists. That's why with the collapse of USSR suddenly the very well educated engineers and scientists had to become taxi drivers and this caused huge social issues. It was so widespread that it become a stereotype in the west. Of course it's not just the rocket scientists but pretty much anyone employed or their sector protected by the government.
Because those people don't know how to operate in the new system, they will fail miserably. Another example could be An archeologist who was able to climb their career through their academic success will finding out that archaeology doesn't have much market value and their lives will be ruined. For decades no one smart will want to do this and they will lose a lot of cultural and historical heritage will be eroded by corrupt people who find a market value in it but have no knowledge in the matter or ethics.
It's a stereotype for Eastern European women becoming prostitutes in the West. Apparently Javier Milei promised to legalise selling organs, so it is possible that the Argentinian stereotype be people with missing organs. This happens because sometimes people are desperate and sometimes because they lose fate in their future and want the quick buck.
System changes are extremely stressful and can create huge social issues that can last for generations.
What do you think will happen if significant number of government employees can't find jobs nearly as good as those they used to have? What do you think it will happen to people who are 40+ years old, having school age kids and they know one job that no longer exists?
All the Russian engineers who become unemployed with the collapse of USSR were not leeches, they build some of the greatest machine mankind ever build and the scientists made huge contributions only to become taxi drivers. Those who can suck up the system will be able to suck it. No matter how libertarian, they will find out that infrastructure doesn't spontaneously occur in nature and there will be huge government spendings and the leeches will leech those.
I've been through this twice, I don't have faith in revolutions. If they actually manage to the things they say will do and govern properly and have sane government, it will take decades before it stabilises for the society. This is because people live around 80 years and they have different abilities and different capacities to adapt at different ages. It's very fundamental to human nature.