Empirical evidence shows that the global south is getting poorer than the global north.
Very heterodox economists give their explanations which include imperialism and financial exploitation by the World Bank.
However, China is the only country which breaks the mold. Heterodox and Marxian economics reasons are offered. What is missing from the article is a world-systems analysis which says that the world is divided, not just into core and peripheral countries but there are also countries in the capitalist semi-periphery. These countries, like China, have unique characteristics.
Read Michael Roberts