Deferring taxes is essentially an interest-free loan from the government to you. You can take that money, invest it, and then keep most of the earnings when you eventually pay the taxes.
There are also some loopholes where capital gains taxes deferred until after death just don't get paid at all. This is the "step-up basis" where your inheritors get to reset the basis of capital assets and neither you nor they has to pay taxes on the capital gain.
Yes, and when you do pay it's a lower "real" tax (due to inflation)
This is what they call "buy borrow die" or some such. Buy an asset, borrow against it, die to reset the basis. Your estate will still have to repay the loans, but... that one part I don't really understand. Do they just refinance, taking a new loan against the newly valued asset?
This all seems to benefit from low interest rates. Was it a thing in the 90's? Or even the 80s when rates were much higher?