[VNM] The relevant chapter is #3.

It is not. As I said, the authors do not attempt to justify the Utility Hypothesis, they assume it. Chapter 2 (not 3), page 8: "This problem [of what to assume about individuals in economic theory] has been stated traditionally by assuming that the consumer desires to obtain a maximum of utility or satisfaction and the entrepreneur a maximum of profits." The entire book is about the implications of that assumption, not its justificaation, of which it says nothing.

Improvements to this version have been made by Savage and by Anscombe and Aumann.

Neither do these authors attempt to justify the Utility Hypothesis; they too assume it. I can find Luce and Raiffa in my library and Myerson through inter-library loan, but as none of the first three works you've cited provide evidence for the claim that people have utility functions, rather than postulating it as an axiom, I doubt that these would either.

But now you deny having asserted any such thing:

Did I assert [the Utility Hypothesis]? Where?

Here you claim that people have utility functions:

I would prefer to assume that natural selection endowed us with a rational or near-rational decision theory and then invested its fine tuning into adjusting our utility functions.

And also here:

Parents clearly include their children's welfare in their own utility functions.

Here you assume that people must be talking about utility functions:

If you and EY think that the PD players don't like to rat on their friends, all you are saying is that those standard PD payoffs aren't the ones that match the players' real utility functions, because the real functions would include a hefty penalty for being a rat.

Referring to the message from which the last three quotes are taken, you say

I explicitly state here that the justification of the theory is not empirical.

and yet here you expand the phrase "prefer to assume" as :

I mean that making assumptions as I suggest leads to a much more satisfactory model of the issues being discussed here. I don't claim my viewpoint is closer to reality (though the lack of an omniscient Omega certainly ought to give me a few points for style in that contest!). I claim that my viewpoint leads to a more useful model - it makes better predictions, is more computationally tractable, is more suggestive of ways to improve human institutions, etc.

These are weasel words to let you talk about utility functions while denying you think there are any such things.

How would you set about finding a model that is closer to reality, rather than one which merely makes better predictions?