For a long time left-leaning theorists had argued that the difference between the countries of the North and the South would increase steadily, that the countries of the capitalist periphery could never catch up economically with the countries of the capitalist core zone.
This left underdevelopment theory is refuted by the facts. Nevertheless, the results are contradictory. Compared to the USA, southern Europe and above all Southeast Asia have caught up economically. Southern Europe reached over 50% of US living standards in 2010, Southeast Asia 40%. Latin America in general has lost ground like sub-Saharan Africa.