The wealthy use a progressively more and more marginal amount of their income for necessities. Consequently, their income gets pumped into assets, which produce

The wealthy use a progressively more and more marginal amount of their income for necessities. Consequently, their income gets pumped into assets, which produce still more wealth for them. There are different ways of taxing people. You can tax their income, you can tax their capital gains, you can tax their wealth, you can tax inheritance, etc... It is basically understood at this point that if wealth is relatively untaxed, wealth inequality grows. If wealth inequality is large, society destabilizes. The example of a doctor isn't really meaningful in isolation. It is also pretty reductive to think only in terms of simple percentages and how much of "what they have earned" they keep. Different parts of the world have a different cost of living. If you live in the states and make $200K per year, you are capable of living a comfortable life anywhere in the country. If you make $400K, how much more comfortable? What about $800K? If the doctor is making $800K and their tax rate drops by half, then what? There is a sense of how much is reasonable for someone to contribute back to society, and if the amount they contribute drops significantly so that they are perceived as not contributing enough, then it is fair to regard that tax cut as a handout.