Those retirees would have to spend their entire personal account to make sure they remained out of poverty in their older years, according to tentative administration projections."
When the retirement age was originally set, it was around the life expectancy of that time. The life expectancy has lengthened while the social security retirement age has stayed put. Moving to personal accounts will increase the amount of time people work, because the longer they work the more money they get. Whereas now the more you work, the less you get. This will be a personal decision made by each person based on their individual situation. Of course, lengthening the time people work might also extend life expectancy, but that will be an unexpected, unintended consequence.