I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Studies on income inequality and growth have sometimes found evidence confirming the Kuznets curve hypothesis, which states that with economic development, inequality first increases, then decreases. Economist Thomas Piketty challenges this notion, claiming that from 1914 to 1945 wars and "violent economic and political shocks" reduced inequality. Moreover, Piketty argues that the "magical" Kuznets curve hypothesis, with its emphasis on the balancing of economic growth in the long run, cannot account for the significant increase in economic inequality throughout the developed world since the 1970s."? 

As economic inequality has increased, what idea found within the Kuznets curve hypothesis has come under doubt?