Perhaps not a phase-out program, but a progressive shut-down program, as a trade off between peak performance and total lifespan, where the characteristic patterns of ageing is what allowed humans to live much longer than other animals around the same size. Similar to the idea in this comic: https://www.badspacecomics.com/post/the-suit
By this logic, as a hedge against sudden death around ~50, the human body start cranking down the output of its diverse subsystems by then, to maximize operacional life, just like NASA engineers from time to time turn off instruments in the voyager to keep it operational against the odds. This is what we call ageing.
I think this argument only makes sense on the surface level. If it was the case that humans hit some hard limit to growth (perhaps running out of 'room' to grow, or losing the ability to process new energy, etc), then I think it could make sense to do this sort of 'graceful decommissioning' behavior, which we'd come to know as aging. But is there a hard limit we hit, aside from the aging process itself? None is obvious to me.
What limitation is our body pushing off by 'choosing' to age, instead of continuing as normal?
Edit: Regardless of the validity of the argument, I loved that comic, thanks for sharing.
It's commonly thought that if your cells kept dividing the way that they do when you're young and they accumulated genetic damages you'd get cancer more often.
AFAIK most cells can only divide a limited number of times, because the dna gets shorter with every copy. There is a finite bit of padding at the end (that you're born with) and once that's used up through too many copies, the cell can no longer divide (supposedly).
but we can just make another human with new cell timespans? something doesn't add up. also, men without kids age slower but die early while men with kids age faster and live longer.
By this logic, as a hedge against sudden death around ~50, the human body start cranking down the output of its diverse subsystems by then, to maximize operacional life, just like NASA engineers from time to time turn off instruments in the voyager to keep it operational against the odds. This is what we call ageing.