There is no such thing as income inequality. Income inequality is a faux concept conjured by academicians.
Income means wages through time. Any wage is a price.
Anyone working sells skills through time and buys wages. Robert Downey Jr. has a higher income than you because his skills expressed through time — his acting — are in much higher demand than yours. People are willing to pay winning bids for his skills at a much higher rate than yours.
There are skills inequality — Downey can act on a global scale — and you can not.
The true cancers killing the tree of goodness are Crony Politics, Crony Governance and Crony Regulatory Capture.