In the 50's if you were in the top marginal tax bracket you were taxed at over 90%. Yes 90%!!!
So if you made a million dollars... congratulations you get to keep $100,000 of it.
That isn't how tax brackets work. You would get taxed 90% on everything you make over and above the lower tax brackets. Your effective rate would be lower.
But that doesn't take away from your point.