Receiving a relatively low official salary (Bezos's Amazon salary was $81,840 for many years).
Not receiving dividends, so the wealth remains in stock that is not taxed annually.
Borrowing money against their stock holdings to fund their lifestyle. Loans are not considered income and are therefore not taxable, and the interest on the loans can sometimes be used as a deduction.
Lower courts. The track record of this administration at the SCOTUS is 90%.