@parados,
By your own cited census data the % of the population over 65 increased from 18% to 19% between 2000 and 2010. Meanwhile, as life expectancy rises, many people are retiring later. Additionally, the ageing of our population is a continuous process, while the labor force participation rate was flat for at least a decade before the recession and Obama taking office, when the steady decline in the labor participation rate began. I don't have an explanation for the prior flat rate: perhaps the Brueau of labor statistics does.
You have a point here, however it explains, at best, about a quarter of the measured drop in labor force participation rates.
The truth is Social Security disability rolls and Food Stamp participation have expanded enprmously; work force participation is down well below expected levels; and a growing fraction of workers are part time or at 30 hours/week and making less annually than before. All of this is tracable to the sluggish recovery we have seen from the 2007/8 recession (the slowest in two generations). That is largely tracable to the foolish and largely non productive regulatory environment created by Democrat-initiated financial, Labor, Environmental and Health Care legislation, and the President's excessive use of executive power. Together they have created an uncertain and unpredictable business environment. Companies are sitting on cash and credit, unwilling to invest it in an uncertain regulatory climate, and the economy is stagmating as a result. Sadly for us, the Obama prescription is simply more of the poision that caused the problem.