interestingly i take it more from an intergenerational contract that at some point it's the duty of the old to senesce and optimize for the good of subsequent generations.

As I understand it this intergenerational contract used to be quite strong as people would see that previous generations invested in them and as a pay it forward sort of mechanism, they would in turn pay it forward to generations that proceed them .

I suppose there was some "take care of me when I'm old" in the intergenerational contract too, but I understood that as secondary to the propagation aspect...