"For as generous as progressive seems when taken away from the uber-rich, it actually is a penalty for those just on the cusp of wealthy, and keeps them stuck i

"For as generous as progressive seems when taken away from the uber-rich, it actually is a penalty for those just on the cusp of wealthy, and keeps them stuck in middle class without an effective means of pushing past it." That is assumption somewhat based on the current marginal tax brackets. There would be no reason that a progressive tax could not be designed so that moderately wealthy individuals would pay a similar effective tax rates compared to the "middle class", and then require the to X% pay significantly more (those earning more than say 10 million, for example). Or better yet, do as Warren Buffet himself proposes, which is harmonizing the capital gains and marginal tax brackets such there is a flat effective tax for all income levels. Buffet generally argues that he and his secretary should be paying the same effective tax rate, not that high-income individuals should be coercively taxed. (funnily enough, President Reagan made an identical argument comparing a secretary's tax rate to their boss). A flat tax could potentially be lower for most or all taxpayers, there's nothing in it that requires it to increase the tax burden.