It’s true the income-tax brackets were higher then, than they are today.
However, however, however.
Nobody, but nobody, ever paid 90% (or whatever) in income taxes.
The rate was on the books, but nobody paid them.
Loopholes; managing one’s money so as to have to pay as little as possible in income taxes.
Old Man Joe Kennedy was a pro at doing that.
Hemingway was scrupulous in staying in Cuba at least six months and a day, every year. It wasn't just because he loved the place.
I'm not sure but I seem to remember someone telling me that back then most people didn't pay any income tax at all since the lowest rate didn't kick in until around $10K. Back then if you made $10K it was something. I think of the scene in the movie It's a Wonderful Life where George Bailey is offered a job making $20K/year and he's in shock.
If the tax rate is 90% but nobody makes enough to pay it, it's not doing any economic damage. The problem comes as inflation kicks everyone's wages up but those tax brackets don't move with it. This is why inflation is such a stealth tax.