Some agents, but not all of them, determine their actions entirely using a time-invariant scalar function U(s) over the state space.

If we're talking about ascribing utility functions to humans, then the state space is the universe, right? (That is, the same universe the astronomers talk about.) In that case, the state space contains clocks, so there's no problem with having a time-dependent utility function, since the time is already present in the domain of the utility function.

Thus, I don't see the semantic misunderstanding -- human behavior is consistent with at least one utility function even in the formalism you have in mind.

(Maybe the state space is the part of the universe outside of the decision-making apparatus of the subject. No matter, that state space contains clocks too.)

The interesting question here for me is whether any of those alternatives to having a utility function mentioned in the Allais paradox Wikipedia article are actually useful if you're trying to help the subject get what they want. Can someone give me a clue how to raise the level of discourse enough so it's possible to talk about that, instead of wading through trivialities? PM'ing me would be fine if you have a suggestion here but don't want it to generate responses that will be more trivialities to wade through.