Which is, like, $15,000 a year. That's substantial -- in fact it's more than most people pay in taxes at all!
We should start from the fundamental question: why should this guy pay more than Joe Schmo at all? Why shouldn't the tax bill be spread equally over everybody, so it's (say) ten thousand dollars per head? That would be what I call "fair".
It's also not possible because some people just aren't getting off their butts and earning $10K per head, but that should be considered a deviation from fairness. We should look down upon those with below-average incomes as jerks who aren't working hard enough to pay their share.