That "people would make the right decisions" argument is so provably wrong: They very obviously DON'T make the right decisions, because if they did they would have a fortune saved for their retirement by age 65, instead of shiny new car leases every year and $6 cups of coffee from Starbucks. Social Security is the bare minimum so you don't starve to death or have to beg on street corners. Paying into Social Security in the richest states at least gives you the option of retiring more comfortably in a poor state or foreign country. I would hate to depend on Social Security alone I paid in on a minimum wage job.

People might make the right decisions if we bothered to educate them, but we don't. That's why we desperately need Social Security.