Reply #125: "regardless of their contribution" is a right-wing way to look at it

[Mairead]

because it focusses on the amount of money being taxed. Rightwingers like to pretend everything happens in a vacuum and results are entirely the result of individual merit or lack thereof.

But as people as different as Teddy Roosevelt, W.E. Deming, and Warren Buffet have pointed out, the socioeconomic environment within which wealth is accumulated by some but not others is a system, and whether some individual becomes wealthy or stays poor is more a function of the system itself than of the individual's absolute skill level. As Buffet put it, he could never have become wealthy in, say, Rwanda. His ability to become wealthy depended almost entirely on living in the USA during the 20th-early 21st c., an environment that strongly favors the particular kind of skill he has.

And, of course, as another example we have G.W.Bush, who is vastly wealthy despite having no useful skills at all. His wealth is due 100% to the system because it allows wealth to be accumulated without limit across generations. If our system instead only rewarded skill and effort, G.W.Bush would be a skid-row bum somewhere, or dead. He certainly wouldn't be wealthy or sitting in the WH.

So yes, a perfectly progressive tax system would result in everyone having the same amount of disposable income.