Until the issue of what constitutes income is resolved in a fair and consistent way, any discussions of the value of relative tax rates by income level are meaningless. Wealth is accrued at the high-end through a variety of channels, both directly and through indirect vehicles that provide access to wealth.
(Low income people have little wealth to speak of, and comparably little income, so ignore the bottom quintile.)
As for the upper four quintiles, wealth distribution has shifted dramatically away from the middle quintiles and towards the upper quintile over the past 30 years. Labor hours per household have increased and household incomes remain stagnant. Explain the relative increase in wealth in the upper quintile? Income, no?
The tax system is skewed away from the middle class and towards the wealthy through the use of sophisticated tax shelters and tax accounting mechanisms. A discussion of tax policy isn’t meaningful until it addresses tax avoidance and the definition of income (year over year accumulation of wealth).
