It's hard to imagine anyone would keep working for that $400,001th dollar if they only got to keep 16 cents of it. Surgeons, for instance, can literally stop taking patients and go to Aruba when they get near the bend. High-dual income households is another example-- imagine a double-physician household where one of them is taxed at 84%-- they'd save money by one of them not working at all considering daycare expenses.

Actual taxes on the 1% in the 50s weren't really that much higher, despite the marginal rates-- https://taxfoundation.org/taxes-on-the-rich-1950s-not-high/