No interest on reaching agreement on cryo success probabilities, when this seems like an absolutely crucial consideration. Is this indicative of people who genuinely want to get to the truth of the matter?

You're trying to get to the truth of a different matter. You need to go one level meta. This post is arguing that either position is plausible. There's no need to refine the probabilities beyond saying something like "The expected reward/cost ratio of signing up for cryonics is somewhere between .1 and 10, including opportunity costs."