According to empirical laffer curve studies, median earners in America start taking their foot off the gas pedal when you tax more than 33% of their wages, but you can tax 73% of billionaires' income before they begin to dial back their contributions to the economy.

We taxed our top earners 90% in living memory, which was naively high and absolutely caused distortions, but their current crazy low tax rates are a ridiculous policy failure. We could absolutely fund a small basic income by fixing this alone.