There were two things he could have done, starting at the beginning, when he had some momentum and a tiny bit of doubt about his abilities.
1- Fix the import taxes and red tape.
Nobody, of any political persuasion, disagrees that this is a mess. Milei, as a libertarian, thinks the way to do this is completely open the market, and let the chinese put every argentine business out of business.
This is a political non-starter- he has what, 3 deputados?
The only way anything gets done in politics, anywhere in the world, is compromise and hard work of finding a deal that will satisfy all the major players- which in this case includes manufacturers, agriculture, importers, unions and workers, and the whole political spectrum.
Its do-able- Germany, for instance, exports all kinds of things and protects its employees and businesses, but its also possible to order on amazon or ebay there. You have to have many categories of imports, some taxed, others not, some things protected and subsidized, others free. Its hard, it takes time, and you have to work well with others- and Milei is incapable of all these things.
But his sponsors, basically the casta and the 100 families that own everything, wont let him just destroy everything.
2- Tax reform.
Again, nobody, of any political stripe, disagrees that this is needed.
Again, Milei wants a magic bullet that solves everything in one fell swoop, which, in reality, would make nobody happy, and will get zero votes.
Again, it requires a lot of work. A lot of boring administrative work, figuring out who is actually paying taxes, who should pay more, who should pay less, and how to make it fair and equitable to all.
This is not rocket science, almost all of the OCED countries have much more workable, and progressive tax frameworks, there are plenty of options to choose from. Japan, for example, has a LOWER VAT tax, higher wages, higher employment rates, and a manufacturing base. Some of how they do it could be adapted.
There is a whole menu of types of taxes across the functioning economies of the world, and the right combination would yield a similar tax per gdp rate, but spread it to work, and to tax the places where there is income.
Argentina does not have a particularly high overall tax rate as a percentage of GDP- even among South American countries. Its not necessary to raise the overall tax income- just adjust who it comes from, and enforce a simpler but more functional framework.
But Milei just wants to mouth off and be annoying, he is not willing to work.