America's baby boomers—those born between 1946 and 1964—face a problem that could weigh on the economy for years to come: The longer it takes for the economy to recover, the less money they'll have to spend in retirement.

Policy makers have long worried that Americans aren't saving enough for old age. And lately, current and prospective retirees have been hit on many fronts at once: They have less money, they earn less on what they have, their houses aren't rising in value and the prospect of working longer to make up the...