You’re hardly alone in viewing the SS program that way, but (1) it wasn’t designed as a purely investment based plan in the first place and (2) to the extent that it might have operated like an investment based plan, they squandered what was paid in and have to make the payments to you now out of taxes of people like me, who probably won’t ever see an actual SS.
(3) it could never sustain that 60% of the eventual outflow would be the result of what did not even exist when Social Security was created: lifetime support for the indolent and their little bastards....