I think the author was looking at too small a window into Argentina. It still is a pretty decent place to live and it will probably capitalize on Brazil's new growth spurt. Look at the most populous area, Buenos Aires, which has 1/3 of the population and an HDI of 0.923. It's a first world score.

I think Peron was quite positive, and the author forgets to note that before him Argentina was controlled by English companies who took the best part of the profits from the beef industry.