It is also, and I think much more importantly, an issue of WHEN the money is available. And the utility of the money. When people are in their 80's & 90's they cannot do things they could do in their 60's.

I think we are talking about two different things. If a retiree (or retiree couple) at age 62 (or 63, 65, 67, whatever) don't have enough money to properly enjoy their retirement while they still can (before their bodies deteriorate too much) then of course I say to take the social security money and use it. But that isn't what we are talking about here. We are talking about a person/couple that HAS two (or even three) sources of income in retirement and chooses to take the social security money early because of "I can take it at age 62 and invest the money in the stock market".

The case here is a retiree/couple that HAS some money saved, and the choice being made is to either take social security early for that extra cruise or two, or to spend their own savings on that extra cruise or two (while they are still healthy enough to enjoy it). And the math (actuarial and probability and risk) tells us that for the vast majority of such people, it is better to spend your savings and take the social security later. Basically, it's stating that it is better to take a guaranteed level 8% inflation adjusted tax deferred no-fee return for 8 years (age 62 to 70) than to invest in some variable return, taxable, not necessarily inflation adjusted with fees instrument for those 8 years. That's the math part.

Saying someone should deny themselves gratification now in return for gratification in the future is an entirely different discussion. And the age at which denied gratification should end is also another discussion.