See a Washington Post article about the migration of the older long-time unemployed onto the Social Security-run Disability rolls. Once there such individuals rarely return to employment.
As we've noted here at COTTonLINE, this trend is not particularly new. The U.S. experienced a similar phenomenon in the 1930s.
World War I vets who happily worked through the Roaring Twenties found themselves unemployed. They "discovered" war-related disabilities that had previously gone undiagnosed, dare I say even unnoticed.
The 1930s Veterans Administration was overwhelmed with applicants and had to create additional hearing panels to adjudicate and process the flood of applications. I expect today's Social Security Administration is experiencing the same conditions.