The problem is the same as in the political system: institutions like democracy only have even a chance of working if they're backed by a stable system, traditions, informed (to some extent) voting public, and that in the absence of these, democracy starts to look more like Iraq and various Arab Spring countries.
So too it is with economic systems. Liberal trade policies only work if the local economy is likely to be able to adapt and work with the global one. If quality used clothes, let alone new, can be sold alongside local stuff which loses both on quality and price, local industry will either adapt or go out of business. If the entire cultural makeup of the country makes it next to impossible to adapt without enormous pain being inflicted for close to a generation, then liberal trade policies, even though they normally ultimately work, won't (or perhaps one can argue that they 'ultimately' will, but that the cost in the interim is too high).
Protectionism ultimately won't work, and it's akin to painkillers and short-term medication keeping the patient alive and conscious for long enough to die from cancer as opposed to a brain aneurism, but it is what it is.
Videla to the best of my understanding (and I am no expert) simply brought in Western-style trade policies without dismantling the populist gimme culture that predated Peron and was greatly exacerbated by him on his watch. (Not to say that doing that was necessarily easy or even possible). This is the same as deposing Saddam, Assad or Gaddafi and expecting a stable democratic process to take root.
The problem is that in a much more global economy than 40 years ago, there are not many modern equivalents of bartering wheat with Spain. There is China, yes, and Iran - which Argentina is unlikely to want to deal with. Wait, what?