So is Social Security a "Ponzi scheme?" No, it's group insurance, not an investment. You die young, somebody else benefits. Its finances have been open public record since 1936. Do fewer workers support each beneficiary? Sure, but who cares? It's denominated in dollars, not a head count. The Boomers were nearing 40 when the Reagan administration fixed the actuarial tables. No surprises there.
Are longer life expectancies screwing up the numbers? Not really. Most of the rise is explained by lower infant and child mortality, not by old timers overstaying their welcome. Kevin Drum points out that gradually raising the payroll tax one percent and doubling the earnings cap over twenty years would make Social Security solvent forever.
But that's not good enough for the more hidebound members of the $800-a-plate set. See, over 75 years Social Security has provided a measure of dignity, security and freedom to working Americans that just annoys the hell out of their betters.