Depends on how wisely one invested.

Do you think the money you contributed to social security is sitting in some government fund gaining interest waiting for you to draw it out??? I got news for ya...the money you contributed has already been spent on some other guy or gal or child. The only way you'll see any social security payment is if several people continue to work and put their funds into social security. 
To compare social security to a private investment is folly. If you step back and look at social security it resembles more of a ponzi scheme than any type of investment. You buy into social security, what you contribute is given out to someone who bought in earlier, long before you ever get a chance to withdraw funds, and the only way you'll see any return is if some other person buys in...actually several others need to buy in.
Isn't that the definition of a ponzi scheme??