Anyway: The Coming Generational Storm is well worth reading. It shares some general ideas with "What if the Boomers Can't Retire" and "The Great 401K Hoax".
All of these point out that the stock market doesn't throw off enough money to fund all the retirement of all the people who are depending on it to. In 'the good old days' companies put a significant portion of their profits into funding their pension systems (or sometimes not enough, like GM and the Airlines). The "match" portion of the 401K results in far less money, on a per capita basis, going into retirement accounts.
What happens when all the currently 50ish people decide to cash out at age 65? Lots of sellers means prices drop, just when people expect to be able to get out of the market.
The Generational Storm adds onto this the idea of generational accounting and the problems with the multiple pyramid scheme social programs we have: Social Security, Medicare.
Something has got to give at some point. It will probably be a combination of higher ages to beging drawing benefits, benefit reductions, benefit indexing to other income, higher taxes and inflation. \
Those who have saved and /or worked to have a pension will be penalized in favor of those who have not. (Of course at this point the largest source of the old style "defined benefit (ie: 80% of last years pay) pension are government workers. They will probably exempt there pensions from indexing somehow.