Paid back? The SSTF has $2.5 trillion in non-market, interest bearing T-bills. They will be used, and they are being used now, when outgo [benefits] exceeds revenue [payroll tax.] The USG must redeem them.
SS has always been a pay as you go system. The issue is not whether SS will be paid back or not, but rather whether the USG can afford to carry its national debt. The $2.5 trillion in the SSTF is just part of the national debt of almost $14 trillion. The problem is that the USG will have to borrow money or increase income and other taxes to redeem the bonds in the SSTF.
All the graphs and utterances from so-called experts mean exactly nothing. It is graphs and experts that have gotten us into the present situation.
Now you are being silly. These graphs I provided portray the actual situation we are in vis a vis SS. It comes from the SS Trustee reports. We can not sustain SS as currently structured. Demographics and the fact that SS COLA increases [CPI-W] are not linked to revenue make the system unsustainable. These are actuarial statistics. It is really simple math. We must either decrease benefits or increase revenue to make the system balanced fiscally. We did something similar in 1983 when SS went into the red. Personally I prefer personal accounts and privatizing SS except for a small defined benefit program to cover disability and survivor benefits.
Once the access was legal, then the fund was raided. Prior to the change in the legality, the 'trust fund' was off limits and not included in the calculations that you are now using.
These T-bills that you reference are 'non-negotiable'. That means that are in essence, worthless. Regardless of the interest, if any, earned, they can't be traded on the open market. That means they have no value other than the interest they earn.
The real questions are this. What would be the shape of SS is the 2.5 trillion were actually on deposit? What kind of interest would it be earning? If the surpluses hadn't been mis-appropriated/skimmed, would there really need to be a fix?
I am a business man. All the experts' advice; people in the know recommendations; and so on mean nothing. Most of them, if not all, have never had to meet a payroll or make a profit. That is why, every time something they operate goes sideways, they opt for the easy fix of altering the rules like raising the age limit or opting for more taxes.
Finally understand this, the USG doesn't have to redeem anything. The government, i.e. these learned educated fools from the elite, ivy-league institutions are the ones making the rules and not redeeming anything. Just ask the WAMU stock holders. Case in point.