Omega can wipe their memories of past interactions with other particular agents, as in the example I made up. That would make each interaction a one-shot

I wouldn't call a game one shot just because memory constraints are applied. What matters is that the game that is being played is so much bigger than one prisoner's dilemma. Again, I don't dispute that there are all sorts of potential considerations that can be made, even if very little evidence about the external political environment is available to the agents, as in this case. Given this it seems likely that I don't disagree with Vlad significantly.