There’s another aspect to this, that eventually the loans have to be repaid. That may involve selling assets, which would expose the seller to capital gains.
However, if the loan is held until the owner of the loan dies, then the estate gets stuck with that bill. But the estate inherits all the assets at a stepped-up cost basis. The assets are still sold to pay off the loan, but very little will be owed in capital gains taxes.
It’s so common that it’s referred to as the Buy, Borrow, Die strategy that the wealthy use to avoid taxes.
They get permission to hate the people they want to hate. See? They think it is a fair deal.