There's another aspect to consider, perhaps: nowadays it's very easy to get to get that kind of loans with low, low interest rates, well below average market re

There's another aspect to consider, perhaps: nowadays it's very easy to get to get that kind of loans with low, low interest rates, well below average market returns. So, if you have a large collateral, you could just use a chunk of the loan to repay interest. I hope my math is not wrong, but if you borrow $100K with a 3% APR — even mere millionaires can get better terms than that — after 10 years, you've had to pay "only" $35K in interests. You could use part of the original loan to pay that, or you could get a new one, assuming your collateral has appreciated. Neither of those require realizing gains, right? You just keep pushing them into the future, until you finally die and your heirs' cost basis gets reset.