[chrismcb]

Why? The loan didn't get paid back magically. It isn't going to get paid back by other loans. It will eventually be paid with taxable income.

[cheriot]

Someone sufficiently wealthy can push off taxes until they die and their heirs can use the step up basis[1] to avoid them entirely.

There's also a huge advantage in the ability to choose when one wants to pay taxes even if they eventually do get paid. Buffet loves to talk about unrealized gains as a loan from Uncle Sam at zero percent interest.

[1] https://www.investopedia.com/terms/s/stepupinbasis.asp