If you're factoring on income then the person is not rich. Rich people make their money on capital gains. Laws like that would just make the world eggshells for the rest of us and the people who can afford Ferraris wouldn't be bothered.
Defining "the rich" would help. Arguably someone making their money on income is not "rich", they're still moving up the economic ladder. Someone making capital gains, especially exclusively or in majority, is definitely rich.
There's also wealth taxes. Currently a lot of places implement income taxes which actually slows down or halts economic fluidity.
Yes, at max 20%. Yet, the majority of jurisdictions keep taxing income at a much higher rate. As a general rule people working on income are still making their way up the economic ladder while people on capital gain, especially exclusively or in majority, are not.
I'd assume not - the rich anyways hardly get large salaries (I'm sure they do, but the majority of the money they make is probably borrowing on equity).