What requires explaining are the things that created and sustained higher standards of living

"There is nothing automatic about prosperity. Standards of living that we take for granted today have been achieved only within a very minute fraction of the history of the human race, and are by no means the norm among most of the people of the world today. Standards of living far below what we would consider to be poverty have been the norm for untold thousands of years. It is not the origins of poverty which need to be explained, since the human species began in poverty. What requires explaining are the things that created and sustained higher standards of living" (Sowell, Wealth, Poverty and Politics, pp. 1-2). HT to CafeHayak.