The richest people make the majority of their income through capital gains. This can be money that they have invested in the stock market or other businesses. They get dividends and other income from those. And since the taxes paid on capital gain is less then on other income, they can often greatly reduce (or eliminate) most of their tax bill. They let their money, not their "work" be the source of their income.
There was a recent example of this with presidential candidate Mitch Romney. The majority of his income is from investments, capital gain, and trust funds (which make money through investments and capital gain). He is on of the "1%" in the US, but paid no income tax.
That is also one reason that Trump has not made his income taxes public. Much of his income is not from "work" but from capital gains on which he pays almost nothing in taxes.
If a person is never going to be wealthy if his money comes from "work." No one can work enough to be wealthy. Instead people like Gates, Buffet, Bezos, etc get their wealth through investment (even if the majority of that is in their own companies) and not their wages for "working". You can not work enough to rich. You have to invest and make others work for you.