Most people don't have any discretionary income to invest.
So, Social Security is their retirement.
Some put more into Social Security than they take out. This helps so many people.
Social Security is an essential program that helps to hold our society together.
It is not intended to be a personal investment.
I strongly support Social Security. Not everyone is brilliant enough to invest well. Older people are prime targets of investment scams and con artists. I had an elderly aunt who personally foiled a ring when she was in her 80s. I happen to be very proud of her. But she was extremely intelligent even at an advanced age. Most seniors are not so quick.
Further, who wants to have to watch the stock market or handle a small portfolio of investments (which no honest broker could afford to handle) when they are in their 80s or 90s? I know someone that age who dreads the arrival of her bank statement each month because just balancing that is a huge burden.
I'm retired. I rely on Social Security. It is an absolute necessity. Without it, young people would have to live with and support their parents. That would be much worse for most young families than is the cost of paying for other people's Social Security benefits.
Remember, those of us who are now on Social Security paid generously for our parents and our grandparents. It is the American way.