Based on your response here, I don’t know what you were trying to say.

Wealthy people don’t pay income [tax] very much at all, their income is made via capital gains.

Also consumption based taxes are the primary [taxes the rich pay,] so the richer you are the less [taxes] this will be as a percent of your income.

I thought you were complaining about the authors of the study not considering capital gains taxes, but it wasn’t very clear.