Loopholes mitigated the 90%. The rate was cut and loopholes were closed at the same time to make the on-paper tax rates actual tax rates.
Comparing a 90% tax bracket then to 90% tax bracket now is comparing apples and oranges.
Comparing a 90% tax bracket then to 90% tax bracket now is comparing apples and oranges.
Some tax shelters were eliminated/reduced in their effectiveness, shifting some of their wealth gain through the year to being classified as actual income.