Current employees pay the benefits for retirees. It isn’t a Ponzi scheme, because there are no investments, or investment returns. It’s pay as you go.
I know it can look like one, because it seems like current beneficiaries are getting so much now that future beneficiaries will get nothing.
I believe that scenario is unlikely. Yes, we aren’t paying enough in right now to fund future promised benefits. But that can be fixed pretty easily. We’ll reduce benefits, or increase the burden on current employees. Most likely we’ll reduce benefits.
However, we really don’t know what will happen in the future. The assumption is that the workforce will decline and the number of retirees will balloon, leading us into a retirement system that runs in the red. Any of these assumptions could be wrong. Immigration could balloon, leading to a huge increase in workers, and more money for Social Security. Baby Boomers might all die suddenly, of cancer, leaving the system overfunded.
Personally, I think that once we have a gazillion baby boomers who are old, and needing all kinds of help just to move around, we’ll open the doors to immigrants, as they will be the only ones willing to clean our poop and piss. People who are against immigration, in my humble opinion, have their heads up their asses, and are clueless about the future. Let them lie in unrine-soaked beds, because there’s no one available to clean you up.