Thomas Piketty
Thomas Piketty argues that capitalism does not naturally correct inequality, but instead drives a widening gap between the rich and the rest through the mathematical certainty of compound interest.
Piketty's famous formula r > g asserts that returns on investment historically outpace overall economic growth, leading to inevitable wealth concentration.
The mid-20th century period of lower inequality was a historical anomaly caused by the destruction of capital during wars rather than a natural feature of free markets.
To prevent a return to the rigid class structures of the 19th century, Piketty proposes a global progressive tax on wealth to redistribute concentrated assets.