It's mostly because people suck, but there's some altruism in there as well
I think Aumann’s assumptions are unrealistic. From a Bayesian point of view, almost all of your beliefs, you hold them because of a large number of different experiences that you had, that you have forgotten the details of. You do not have a set of “common knowledge parameters”, similar in size to the number of world states, shared across all participants.
I disagree with the inclusion of “politics” it has reached peek derangement and the leadership shows it. Not discussing the system angle itself but just the individuals - I don’t say everything was better before but we have truely given birth to some clownish people on both sides of the isle. At that point an honest plumber could do a better job and I don’t think that’s factually wrong. To give these people the benefit of an expert is a bridge to far for me. Just my five cent