To put another way, the average tax rate paid by the bottom 50% has dropped from 4.92% in 2001 to 3.11% in 2020.
Bottom 75% has dropped from 7.47% in 2001 to 5.35% in 2020.
The top 1% also dropped in that same period. Going from an avg tax rate of 27.6% to 25.99%. However, as you see in the graph above, the share of taxes paid by the top 1% has increased from ~34% to 45.8%. This appears to be mostly driven by the top 0.001% / 0.01% of wage earners. Both groups grew by about 40% in that time period.
Lots of moving parts, but there's obviously a concentration of wealth effect. But how much of that has been driven by tech, and by increased economic activity due to lower tax rates, and increased stock trading resulting from lower cap gains tax rates?
https://www.irs.gov/statistics/soi-t...and-tax-shares