Doesn't really explain Argentina to nearly the same degree as e.g. Brazil-/which The Economist has written about at length over the past couple of years.
Argentina is a great place for ranching and certain crops, but it has very little mineral wealth. I would hazard that the two most likely reasons for South America's slow progress are that its colonies were attached to ailing empires, and that a rugged and challenging geography made unification difficult to unimaginable. American history has no analog to the horrific War of Triple Alliance, a historical microcosm of the continent's diplomatic challenges.
Not to mention that Argentina was doing quite well for itself at the onset of the 20th century- unfortunately political instability and other challenges hamstrung it since then. If some rolls of the dice had gone differently, it would be solidly in first place status by now, same as Chile.
That was my main point. Given different political culture and other factors along those lines, southern South America may not have the great resources and land mass that the US did and does, but you can't really write them off for geographical determinism reasons. Were those countries really in a worse position with respect to resources, climate, etc. than, say, Australia?
