[camikazeg]

I think that you inadvertently pointed to a piece of the puzzle that is pretty important, but retirement communities are a problem, not a solution.

The ideal city is habitable to people of all ages. I don't know if you can make it happen with a top down approach, because I think that it is cultural, but in some cultures the old people are involved in the lives of the young. They are active, they assist with childcare, they pass down old recipes, they bring multi-generational families together, etc.

Ushering the old off to separate communities to die sounds pretty miserable.

Disclaimer: I'm (hopefully) going to be old some day.