We had high tax rates which is entirely unrelated to the prosperity of the 1950s which was based on the USA comprising 50% of the world economy.

We cut the rates in 1983 and took in more revenue overall which indicates that a top marginal rate can be set high enough to encourage tax fraud, tax evasion, and tax avoidance. This is what Laffer suggested at a cocktail party and is now known as “The Laffer Curve”