This has been going on since the sixties. Half a century is not "a few decades". The military regime got entangled with fights against the syndicates (which were a strong political force back then, and are mostly toothless now, with the exception of the truck-transport syndicate), and dismantling the national industries was used as a resource to weaken them. Also, they systematically killed and "disappeared" basically anyone who got into politics that didn't agreed with hem. So they destroyed both the economical and the political basis of the country. The people who took over after them came from what survived their culling: most of the people who could have grown with a different point of view were dead. In that light it isn't that surprising that Menem's government in the 90's followed a similar policy of dismantling the local industry. Under the pretense of amassing funds to fight inflation, he basically sold all what remained of the national industries, creating a nice but unsustainable period of wealth. Following that, De la Rua's government basically did nothing to address the issues, and that's how we got to the 2001 crisis.

This is obviously not a complete explanation, but it works as a highlight of some of the structural causes of Argentina's situation-