RE: It isn't immortality but to age well.

We need death to adapt (evolve) to a changing environment. The idea of immortality could only work (and not then either) if we were in a static universe where nothing around us changed.

I definitely agree. A constantly changing environment needs constantly adapting lifeform (and death is a part of it).

The ideal is holding onto productive life, healthy life. ... It is the decline, the loss of productivity that we dread.

This is profound. This is also what I hear from my grandparents and elders from the community. A productive and healthy life is what we should be looking forward and not the infinite life. Thank you for sharing, @agmoore!
!PIZZA