SS puts 100% in treasuries. How do you figure putting 30% in stocks triples your return. In fact, if you are looking forward, you can't say for sure which of these two strategies produces the best return over 5, 10, 15, etc. years.
It's easy to say that putting 30% in stocks and 70% in t-bills will triple my SS rate of return because for someone my age, 36 year old male, will only receive about a 2% real return. Balanced stock portfolios average a real return of at least 6%.
Those born in 1960, for example, are currently calculated to receive a real rate of return, on average, of less than 2 percent on their cumulative contributions. - Testimony of Chairman Alan Greenspan before the Committee on the Budget, U.S. Senate, January 28, 1999
By comparison, the real yield on a 30-year inflation-indexed Treasury Bond in todays Wall Street Journal was 2.729%.
In other words, the government is paying me less than the treasury rate.
In addition to being low, rates of return from Social Security must be viewed as risky because they are subject to change from future political actions that will be needed to ensure long-term solvency of the program.
Also, my wife's contributions will add zero to our benefit when we retire. Considering the money she's already contributed, we'll be lucky to break even. Oh yeah, the 2% return Greenspan mentioned doesn't help if I die before age 67. At least if I can invest my own funds I'll have a nice lump sum to leave to my kids.