The growth of those schemes requires people to continue to pay money into them.

This ponzi scheme is either my poor communicating, or is a feature of many pension systems around the world.

(http://www.independent.co.uk/news/world/politics/a-look-at-p...)

I agree it's not sustainable. What do you suggest? How should people fund their old age?

Prisoners are already being used to care for other old age prisoners. This moving NY Times article is fascinating. (http://www.nytimes.com/2012/02/26/health/dealing-with-dement...)

Fun sci-fi noodling would have criminals being sub-contracted into institutions that care for poverty stricken old people. The prison / elderly care industrial complex grows to a huge evil empire. (Throw in a bit about making and selling coffins and it's complete.)