Our elderly citizens, who can no longer do physical work, should be employed in the knowledge work industry. Their minds should be put to use in search, analysis and synthesis, and we can do so with relatively little infrastructure investment. They know how to read and write already, and they know what their interests are. At the very least, they should be blogging articles about their areas of expertise, but some of them might find that they are adept at protein folding or participating in some other large-scale pattern recognition and processing problem. We don't need them to work quickly, we just need to empower them to work on these problems if they would like to.
Personally, I would like to spend my formal retirement investigating the many areas of human knowledge to which I did not apply myself during my employment, and perhaps discovering a new one at which I am adept. I don't want to spend my whole retirement playing Scrabble and waiting for death. I want to learn and help solve humanity's big problems, one drop in the ocean at a time.
Mokalus of Borg
PS - I may feel different later in life.
PPS - In fact, I'd basically count on it.