Do you have a link or article that shows this? I believe it, I'd just like to see numbers to support it.
https://taxfoundation.org/top-1-percent-tax-rate/
Top rate went from 50% to 28%, then back up, then down, then up, but percentage of all federal taxes paid has been slowly rising from 26% to 37%.
It’s higher now despite the rate being lower now (because there were many more ways to avoid tax back then).
1945-1970 is ranging from 35% to 45% -- and it definitely won't average to 45%, which it only reaches once
2000-2017(?) is ranging from 30% to 42%
You've basically taken the high point of range 1 and compared it to the low point of range 2 -- and "a bit higher" doesn't really cut it when you're talking about what looks to be about 37% for the latest datapoint... about half the distance between your cherries.
There are tons of loopholes when rates were 90%. When rates were dropped, loopholes were closed.
The percentage of total taxes paid by high income earners has increased over time, not decreased.