One economist sketched a rule for inequality — on data he admitted was thin
In 1955, Simon Kuznets proposed that as a country develops, inequality first rises, then falls, forming an inverted U — though he flagged the evidence himself as scarce, with the 'rising' half resting on a handful of data points. The 'Kuznets curve' has since been widely challenged: several economies grew while inequality fell, not rose, and modern critics like Thomas Piketty argue there's no automatic decline built into growth at all.