Thanks for mentioning. Even more relevant to the topic is the most social security program is practically a Ponzi scheme. Straight out off Paul Samuelson's mouth...

“The beauty about social insurance is that it is actuarially unsound. Everyone who reaches retirement age is given benefit privileges that far exceed anything he has paid in. . . . Always there are more youths than old folks in a growing population. More important, with real incomes growing at some 3 per cent per year, the taxable base upon which benefits rest in any period are much greater than the taxes paid historically by the generation now retired. . . . A growing nation is the greatest Ponzi game ever contrived.”