This is an explanation of reality in terms of decision-theoretic heuristics we carry in our heads, as a notion similar to morality and platonic truth. This is of course a mere conceptual step, it doesn't hand you much explanatory power, but I hope it can make reality a bit less mysterious. Like saying that Boeing 747 is made out of atoms, but not pointing out any specific details about its systems.

I don't understand what exactly you refer to by reality-fluid, in what sense you see an analogy, and what problem that points out. The errors and confusions of evaluating one's anticipation in practice have little bearing on how anticipation should be evaluated.