SS does not even give a participant a 5% return on "contributions." (I have 10 years of EE bonds yielding more than that: 1984-1993, and the bond principal is mine as well - not so with SS extortion). And I was not annuitizing the fund and determining a fair payment - requiring a mortality table, and inflation projections. I'm just pointing out that the SS admin could pay me their determined benefit forever without depleting the hypothetical fund, in fact it would increase over the years (except for the real world facts you cite - the "lock boxed" fund never did, nor ever will exist - except as foul lies from the uber corrupt politicians).
More to the point, I believe that my example is ubiquitous, that just about every participant in the SS scheme could demonstrate similar theft of their earnings, and current payers could easily do better by taking their SS contributions and buying "riskless" EE bonds even, not to mention 1000 other better places to invest. Perhaps our unhappy but cognizant victims would reject the scheme at last, and demand its repeal.
I'm not considering inflation at all. Do the calculations yourself, take out your SS annual report, put the numbers in a spreadsheet (employee + employer contribution). Apply a 5% annual return on the accumulating fund, and see for yourself what it amounts to at expected retirement, or anytime for that matter. Then check to see what SS will benefit you with at the time you qualify.
Going forward, you will also grant me that the CPI-W figures are determined by the government, and "curiously" seriously understate inflation - giving no real inflation protection to SS recipients (food, healthcare, services & energy being big items for them).
One easy way to save on SS, the biggest US budget item, lie. Next, of course, for our viper filled "government", is to deny life-extending health care measures to SS recipients, on the basis of cost/benefit, you see. Doubt me?