I see what your trying to get at with your example i do. In a broad sense it's it is a net loss. Depending on market conditions*.

However your example hinges on the idea that young kid has a job and could use that additional 6.2% to pay down loans. However if social security were to go away and old people were to work longer there is a good chance that young kid wouldn't be able to find a job as old people need to continue to work longer.

Essentially, your paying a small amount of your income so that old person in that company you want to work for will retire and you can gradually take the shoes they used to fill.

In doing this you full well understand one day you will be in the same position. Leaving so the next generation can thrive after you.

To your comments on TVoM and RoR of social security. Social security is like any other financial instrument on the market.. if you pay in when the economy is thriving and retire when it's poor you will recieve less then you initially contributed and vice versa.