In the examples you cite, the benefits of progress in technology confound the changes you attribute to developments in policy and government.
If we look to only the recent example of India, it's decreasing poverty rate has been decreasing prior to "lessening of the socialist burdens" that you cite between 1980 - 2000. On page 4, it appears to be trending down in the 1970s and actually becomes stagnant in the 1990s.
Secondly, in the same study, for the time period you cite, India's Gini coefficient, a measure of income inequity, goes up.
http://www.ekh.lu.se/ekhcgu/teaching/401d4/poverty%20in%20in...
I'm all for capitalism, but I think it's misleading to think that it's everything for everyone. There are a lot of examples of great capitalism models as well as socialist models, and I think the idea of excesses in unregulated capitalism (ie. the cost and moral hazard of healthcare) are extensively documented.