I agree on your point that we will all die; as we are all mortals & we have mortal bodies/instruments.
However; I beg to differ on your point about "science fiction".
Ever heard of the "Blue Zones" ? This is not science fiction.
Quoting this from the article:
"Blue Zones" are places of the world where people tend to live longer, healthier & happier lives.
These areas are characterized by a number of lifestyle factors that are associated with longevity, including:
*Plant-based diet
*Regular exercise
*Moderate alcohol consumption
*Sufficient sleep
For your reference:
https://www.bluezones.com/