Social security is an inter-generational transfer. Money paid in and benfits received are unrelated. First recipients got benefits and paid nothing in. My father who died at 94 in 2000, got out much more than he put in and my 86 yr mother still living is getting out much more than she put in. The size of their payments were based on demographics, mortality trends, inflation, social policy, etc. Investment return had nothing to do with it. Baby boomers will get less than they pay in because of these same trends (unless changes are made). Those changes, again, will have nothing to do with investments but rather with desired social policy.
FDR said what he thought the purpose was. I believe him.
Currently it is an inter-generational, that's why it will fail. So you're saying that we should allow it to fail rather than fix it?
If we can provide for retirees without screwing current workers, wouldn't that be better?
The nice thing about investing in the markets is that eventually, you can also get out much more than what you put in. The magic of compounding. You also don't screw the younger generation while you're getting paid.