The dramatic decrease in the worker/retiree ratio glosses over productivity growth. Various government projections confirm that there is no real economic problem in financing Social Security benefits currently in law, nor that "fixing" the program in terms of the Trust Fund will have any appreciable, salutary economic effect.
If one considers workers to population the decrease in the ratio is far less (less than five percent, again ignoring productivity growth). On the other hand, it must be acknowledged that kids are far cheaper than the elderly, including to the public sector.
There is an accounting problem which gives rise to a political problem. We've hashed over this before so I won't recapitulate.
There is a generational issue underlying all this, but it is not the one blabbed about in the media. Tomorrow's workers will, on average, do much better than today's in terms of real wages. They could pay a smidgeon more in payroll taxes, have more after-tax wages than people do today, and fully fund the program. The bigger issue which is ventilated in Gene Steuerle's new book is that with an assumption of some revenue ceiling for the Federal government, more spending on Social Security and Medicare crowds out other programs, including those that could address child poverty.
Now the revenue ceiling is political, not economic, and a key priority is to bust it, but assuming there to be a ceiling cannot be faulted. Federal revenues as a share of GDP have never been higher (since WWII) and further increases are certainly daunting. (Same is true of state-local receipts).
MBS