Asset values and demographic falling-off-the-cliff

Casey Mulligan (an economist from UChicago, the school everyone loves picking on these days) in a guest blog in NYT has invited a lot of derision for his proposal that we are not really facing a shortage of jobs but that of labor (and quite justly for such a slip-shod presentation of ideas).

However, I believe it is worth considering how the impending demographic falling-off-the-cliff (or population implosion - even China and Iran will have more 55+ than 16- population by 2020) might have impacted various asset valuation assumptions? I have been trying to formulate/ formalize this idea, and thought Mulligan's idea that labor shortage might be a candidate. Only, I don't quite believe that the labor shortage is now (in the present), but it is in the near future, and what are current valuations but earnings from future output discounted to the present? If the expectation is that in the near future a sharp demographic decline will sharply decrease the output, it has to be reflected in current valuations. Of course, severe illiquidity in the markets have also caused the effective discount rates to skyrocket (causing valuations to drop like a rock) - but hopefully the policy actions taken and in the pipeline will cause this rise to reverse .. but it will be hard to reverse the demographic falling-off-the-cliff.