Ultra-Wealthy secured loans don't work like mortgages you and I deal with. On a $1 billion dollar asset, they can borrow like 40% of that, with no monthly payments, just one big balloon payment at the end of the 10+ year term with a little bit of accrued interest. They simply refinance in 10 years, and now the asset is worth $3 billion and then they take out an even bigger loan. Because it's a loan, it's not considered taxable income. And the interest payments on this loan are tax deductible. And usually these assets (like real estate, or stocks) often pay out dividends or rental income. So they can borrow on these assets ad infinitum and use the proceeds to continue to reinvest in more hard assets and to fund their lavish lifestyle. They won't directly own a super-yacht, their company will own it and rent it back to them, with the maintenance expenses considered business expenses since it's a rental business. Same with their vacation houses. Along the way they may pay a modicum of capital gains taxes on the stock dividends, but it's usually offset by the tax-deductible interest on the loan itself. Rinse and repeat for a few decades.
At the end of it all, they have enough dividends/rental income, that's paying for lavish lifestyles, and they still own all of the hard assets that they can then pass down to their heirs with minimal taxable events.
