Because there were way more boomers working than retirees, the SS fund was solvent.

Now, there are way more Boomers drawing benefits in proportion to those currently making contributions. (Lifting the cap on withholding would solve that for the foreseeable future)

Also, I think you have drastically overvalued the growth of your contributions as if they were in an annuity.

Yes, you should have, because SS was never designed to be one’s sole source of income in retirement.

So it actually is the Ponzi scheme that some GOP'ers state?

I think you have drastically overvalued the growth of your contributions as if they were in an annuity.

That's exactly how I was viewing it. Why isn't it (an annuity)?

I never got as far as 10% independent savings, for multiple reasons, but I never expected SS to be my sole source of retirement income either.
But just for clarity over most of my lifetime that would have meant 20% of my income as savings (10% independent, and 10%+ of SS) which should most certainly have left me with a MUCH more comfortable feeling than I have currently for the future of my finances.

The GOP calls it a Ponzi scheme because they don’t want to pay back the money they borrowed to give tax cuts to billionaires. If they confuse people into thinking it is something other than the social safety net that it was designed to be, they will have a better chance of robbing it blind.

Ponzi schemes are dependent on the voluntary contributions of the lower tiers of the pyramid to support the upper tiers.

SS, with just a few exceptions, is funded by mandatory contributions from both employees and employers.

Except you didn’t contribute 10% of you’re income, it was only 6.2% (for an apples to apples comparison, you can’t include your employers contribution).

Their 6.2% contributions were added to the value of the company-paid health insurance and many other benefits that they crowed about when giving me excuses not to give me raises that I thought I should have earned!

These are largely rhetorical questions, but based on even my profound lack of understanding of how these things are supposed to work.

What is the difference between a social safety net and a savings account when it’s billions of dollars at stake? Is SS not investing anything? Presumably they can’t fund treasury bonds with it because then it would not be independent.

A self funded annuity would only contains funds you have discretionary control over, which would exclude your employer’s contributions.

Is that SS should have been a (compulsorily) "self" funded annuity. Essentially with similar rules and penalties to taking early distributions from a 401K.
But managed properly, at scale, by an independent agency of the government.
I'd be perfectly OK with some of those trillions being used to fund less fortunate people, unable to work, or for single-payer health care. Especially if we add those healthcare premiums we (and our employers) are currently paying from salary (and benefits), into the SS fund mix.
Thisnk of this thread as a proposal for another possible part of the solution to pathetic payouts to be implemented when saner minds control the economy. As well as a valid question as to what is really being done with those trillions collected in mandatory contributions, because the math doesn't work on the SSA's side either, by any putative savings, interest rates, or distribution calculations I can come up with.

Something a 401k can’t deliver.

In a Ponzi, investors are unaware that the actual investment instrument is a fraud & that their early payouts are funded by lower layers of the pyramid.
Social Security has never pretended to be anything other than a pay-as-you-go program
Your investment analysis is also flawed. Here's why:
If everyone were to do exactly as you say, there'd be another $16-18 trillion chasing investments; every year.
This creates stock inflation until the institutional investors start a sell-off when the prices of EVERY exceeds value from market fundamentals.
Suddenly tens of trillions of value gets realized which causes a bubble collapse. Your proposed return is highly unlikely to come to fruition that were to occur.

Historically and technically true, but conservatives and the right have been having a field day with that for years while pushing the "personal responsibility bootstrap narrative." That shit is hauled out in every right-wing push to cut benefits and raise the retirement age further. The left should be talking about raising benefits, expanding Social Security, and lowering the retirement age. Not buying into the right-wing narrative. "We" can't afford that is not a legitimate argument when trillions are being funneled into the war machine, political pork, corporate government grift, Wall Street schemes, and on and on. A supposed government of the people has become nothing other than a vehicle for funneling wealth to the top 10-20 percent of the economic pyramid while the majority can eat shit and die in retirement after a lifetime of toil. The rest of all political posturing is noise to distract from that fact.

used it and put iou’s in the social security pot, which they have never paid back, way back in the 1990’s.

The IOUs are called "special issue Treasury Bills" and many have been redeemed as the 'trust fund' needed to supplement on-going revenues. And until they're needed, for that purpose, there is no need or even excuse for pulling money out of them.

Another part of the puzzle is that the T-bills are conservative in nature. They are not pegged to any market; they are a monopoly, issued by the government, for a monopsony, the government. Public-issue T-bills increase, these are pegged at the same interest rate.

They vastly underperform the stock market. On the other hand, they are considered safe. Unlike public T-bill market--also considered safe--there is no demand-side chances of a rate increase.