IIRC leading up to WWII Argentina had a per capita GDP roughly 2/3rds that of the US, it's highest point (relative to the US) to date. But they bet on the wrong horse (technically they stayed neutral, and declared war on the Axis at the very end of the war; but the US felt they were Axis sympathizers and treated accordingly after the war)and combined with radical swings in political ideology (far right to far left to far right, etc etc) have never recovered. It should be noted that Buenos Aires is known as the 'Paris of the South' and its subway the Subte is both one of the oldest (1913 IIRC) and busiest in the world. In terms of lifestyle (education, life expectancy, standard of living, etc) they are very similar to Western Europe/US its just in personal income the lag.