What is that saying: You'll get a better response with honey than vinegar. Even the cube root of anyone's income is still a pretty steeply progressive tax.
Wasn't anybody else paying attention in math class. The more people paying any tax the lower all taxes should go.
The following is a little oversimplified but it's better than the system we have now.
In increases of 100x:
A) If just 100 people pay any tax the maximum tax rate is limited to 1%.
B) If 10,000 people pay a tax the maximum rate is limited to 1/10,000ths.
C)If 1,000,000 people pay a tax the top rate isdrops to 1/1,000,000ths.
If 100,000,000 people pay a tax the top rate drops to 1/100,000,000ths
The above plan is roughly equivalent to the following
A) City
B) County
C) State
D) Federal
So there you have it all politicians will try to dumb us down.