The argument seems essentially similar to theories on the evolution of aging that suggest we age because senescence improves evolutionary fitness when the environment changes on a comparatively short timescale [1]. The world changes, therefore a race to the bottom arises for ways to improve fitness that also happen to make life miserable and short for individuals. Miserable and short outcompetes hydra-like immortality or naked-mole-rat-like negligible senescence in the vast majority of niches.