I’ve been saying this for years (via Economix):
“The share of Americans who are working age — old enough to be out of school but young enough not to be retired — is no longer growing. Only about 53 percent of the population was between the ages of 25 and 64 last year, unchanged from 2007 and up only slightly from 52 percent in 1997. Between 1967 and 1997, by contrast, the share grew 8 percentage points, to 52 percent from 44 percent. As more baby boomers retire, the share will begin to fall.”
“Fewer people of working age means, obviously enough, fewer workers. It also means fewer potential entrepreneurs creating new businesses that hire people.”
This also explains part of why stock market returns have struggled. As Boomers retire and switch from stock to bond-heavy portfolios there’s a lot more selling than buying.