Yes, dave, I understand how the funding works, but the current balances in the funds could pay for the benefits of current retirees for many years to come. What many people seem to think is that public employers/taxpayers are literally writing the benefit checks every month for retirees. They believe that when a retiree makes $2,000/month in retirement, that the public employer is cutting a check for $2,000/month for that retired employee. Nothing could be further from the truth (as you know).
The vast majority of the money that funds retiree benefits comes from investment returns (also, as you know), not from “taxpayers.” The remainder is funded by employer contributions and employee contributions. And if those investment returns don’t meet expectations (for future and current retirees, calculated out over the expected lifetime of these current and future retirees), the shortfalls can be made up entirely on the employer side (taxpayers OR other stakeholders like private contractors, developers, special interest groups, real estate investors, etc.), or entirely by employees, or by some combination of both (which is the direction it’s been going for awhile).