&quot;there never was selection pressure favouring people who thrive well into old age and age in supreme health on any chow or fodder without suffering severe degeneration and disease&quot;<p>Can you back that up? Actually having living healthy grand-parents can be a boon to reproductive success: they can take care of kids, while parents are out hunting or gathering. So yes, if you have genetic mutations favoring living old enough to be grand-parents, it is subject to selection pressure.<p>Plus, it&#x27;s been a while since we started caring for old people. In that context, because evolution is all about context, having healthy elderly is also a boon to reproductive success since it doesn&#x27;t divert resources from child care to elderly care.<p>Any genetic mutation that is expressed and results into higer reproductive success in a specific context is subject to selection.