I'm reminded of the story of a self made entrepreneur of the time when tax rates did top out at 90%. After earning a fortune making automobile test equipment, he suddenly decided to start an airline. The airline business was highly competitive and his startup was continuously losing money. When asked why he kept wasting money on it, he replied "why give your money to the government, when you can use it to recruit, hire, and train stewardesses."
It's a true story, and it simply points out what happens when you raise tax rates too high. You simply stop the creation of wealth, which is the engine of any economy.
My father told me one November, 1959? - 60? that he was taking no more work until after the New Year started. I asked why?
He said, “Who takes on the liability that comes with work to make a $1,000, when you will only keep $90 of it?
(Top rate was apparently 91%)