It's the Demographics

This William Bernstein essay from 2003 shows what the next 30 years will be like,

In an era when a small number of people lived past sixty-five, society could easily support them for the very few years they survived beyond that point. Now that citizens are routinely living two decades longer, it is simply not mathematically possible, let alone politically feasible, to expect each worker to support 0.67 retirees, no matter how many coconuts, dollar bills, stock certificates, or Krugerrands they save up in the meantime. It is also not reasonable to expect productive younger individuals to support large numbers of healthy older non-workers.

As Arnott and Casscells succinctly conclude, what we have is not a savings crisis, but rather a demographic crisis. [...]

In order to keep the current worker-to-retiree ratio at 3:1, Arnott and Casscells estimate that the retirement age will gradually have to be raised to seventy-three. Of course, the government need take no action; politically, it will prove far simpler to let poor asset-class returns and low savings force older Americans to postpone their retirements.[...]

If you are currently under forty, you will shortly be traumatized by the sight of large numbers of your parents’ generation subsisting on cat food, and your generation will begin to save prodigiously.