Is a weakness in your argument. Either you can survive without utilons, a contradiction to utility theory, or you wait until your "pre-existing" utilons are used up and you need more to survive.

Utilons don't need to be associated with survival. Survival can be a mere instrumental good used to increase the amount of actual utilons generated (by making, say, paperclips). I get the impression that you mean something different by the word than what the post (and the site) mean.