It seems to be a question of timing. I can see two competing explanations, the spread of market economies and the demographic dividend. Keep in mind most of th

It seems to be a question of timing. I can see two competing explanations, the spread of market economies and the demographic dividend. Keep in mind most of this extreme poverty was eliminated in Asia, and in particular China. Unfortunately China began to liberalize its markets and realize its demographic dividend in the early 80s, at the same time, so I'm not sure about that case. Again in India, liberalization and falling birthrates happened together in the 1990s. 25 years ago was 1993, two years after the dissolution of the Soviet Union. It's an arbitrary time frame, perhaps conveniently selected. That said, market economies spread rapidly throughout the second world during the 90s, and the Soviet subsidies that had kept a number of command economy-leaning third world countries were cut off, forcing liberalization. The most powerful effect of this was the widespread loss of belief in the effectiveness of command economies. With the end of the USSR the major ideological opponent of capitalism collapsed. World historical event -> world-wide change in outcomes is too big a correlation to dismiss. That said it's tough to tease out what is driving what, economics or demographics. I do think that human flourishing occurs when ideology gets out of the way of individuals pursuing their own interests, whether their interests include opening a small business or not birthing children for the motherland. So I am not able to say, "it's because of capitalism," or, "it's because of contraception and female education." I am confident that we can say, "ideology and authoritarianism make things worse."