At this extreme, I think we'd end up relying on backup snapshots. Faulty outcomes are not debugged. They, and the ecosystem that produced them, are just erased. The ecosystem is then returned to its previous state.

Kind of like saving a game before taking on a boss. If things go haywire, just reload. Or maybe like cooking? If something went catastrophically wrong, just throw it out and start from the beginning (with the same tools!)

And I think the only way to even halfway mitigate the vulnerability concern is to identify that this hypothetical system can only serve a single user. Exactly 1 intent. Totally partitioned/sharded/isolated.