You missed the whole point. The point is that, in the framework of marginal utility, the successful aren't being taxed more. You're just looking at the percentage number, which isn't what the theory is based on. The theory of marginal utility is that a 10% tax for someone making $25K per year and a 35% tax for someone making $1M per year is roughly equivalent in terms of utility. They are giving different percentages, or dollar figures, but for the utility that their money gives them, they are giving up the same thing.

The argument is better geared towards whether or not the progressive tax rates are too high. I think they are. But a flat tax doesn't make sense. 30% is a MUCH higher burden on the poor than it is the rich. It's basic economics. I'm find with not rewarding lack of success, but punishing lack of success is just stupid. Poor people, even if they choose to be poor, shouldn't have a higher tax burden than successful people, just because they're poor. It's a ridiculous notion.

The issue is marginal utility. The idea behind the progressive tax is that each dollar on the margin is worth less the more money you make. In other words, the first $10K or so in income is HIGHLY valuable. It pays your food and rent (or a portion of it). That's why it's taxed at 0%. The next $15K (I'm making up the dollar figures - I'm not sure exactly what they come out to, but you get the point) is still very valuable, but not as much as the initial money, so it's taxed at 10%. The next $25K will then be taxed at 15% because those dollars are a little less valuable at the margins. The idea is that by the time you get to the highest bracket, $250K plus, each additional dollar doesn't add as much utility to the taxpayer, so they should be taxed at a higher rate, thus leaving them with the portion of that dollar that is equivalent to the first dollar earned.

If I earn $1 and only $1, that whole dollar is valuable. If I earn $250K per year, and then earn another dollar, maybe only $0.50 of that dollar provides the same value as that original dollar, so the government takes the other 50%.

I'm not advocating it, just explaining the theory since you wanted an answer. The problem with everyone paying the flat 30%, so the argument goes, is that the really poor guy is giving up more than the rich guy because the 30% of his $20K/year salary has a MUCH higher utility than the 30% of someone who makes $1M.