An Aging Society Is No Problem When Wages Rise: Eduardo Porter discusses the question of whether retirees will have sufficient income in twenty or thirty years. He points out that if no additional revenue is raised, Social Security will not be able to pay full scheduled benefits after 2034.
While this is true, it is important to note that this would have also been true in the 1940, 1950s, 1960s, and 1970s. If projections were made for Social Security that assumed no increase in the payroll tax in the future, there would have been a severe shortfall in the trust fund making it unable to pay full scheduled benefits.
We have now gone 25 years with no increase in the payroll tax, by far the longest such period since the program was created. With life expectancy continually increasing, it is inevitable that a fixed tax rate will eventually prove inadequate if the retirement age is not raised. (The age for full benefits has already been raised from 65 to 66 and will rise further to 67 by 2022, but no further increases are scheduled.)
The past increases in the Social Security tax have generally not imposed a large burden on workers because real wages rose. The Social Security trustees project average wages to rise by more than 50 percent over the next three decades. If most workers share in this wage growth, then the two or three percentage point tax increase that might be needed to keep the program fully funded would be a small fraction of the wage growth workers see over this period. Of course, if income gains continue to be redistributed upward, then any increase in the Social Security tax will be a large burden.
For this reason, Social Security should be seen first and foremost as part of the story of wage inequality. If workers get their share of the benefits of productivity growth then supporting a larger population of retirees will not be a problem. On the other hand, if the wealthy manage to prevent workers from benefiting from growth during their working lives, they will also likely prevent them from having a secure retirement.