I once sat down (for almost three days)and computed how much I would have had from my FICA taxes if it had been invested from 1967 to 2015. I took out the 5 years from the service AND the 7 years I was a cop. I compared the amount for each year X the S&P 500 yearly rise/ drop. If this investment would have been made, I could have retired with 2.5 m8llion profit for my retirement fund.
I figured out that the net present value of what I have put into Social Security assuming a 5% rate of return would be at least $3 million. The net present value of what I will receive will be in the neighborhood of $300,000. One of my professors in the finance department in 1975 warned everybody in all of his classes that this would happen. He predicted it about 1963, before LBJ co-mingled the Social Security fund with the general fund to pay for the Vietnam war.
There is an axiom in accounting. Whenever you co-mingle funds financial disaster follows.