I doubt that any system will foom even after humans have left the picture

This seems more like a crux.

Assuming eventual foom, non-foomy things that don't set up anti-foom security in time only make the foom problem worse, so this abdication of direct responsibility frame doesn't help. Assuming no foom, there is no need to bother with abdication of direct responsibility. So I don't see the relevance of the argument you gave in this thread, built around humanity's direct vs. by-proxy influence over foom.