That's an interesting connection to make. I am not familiar with the argument in detail, but at first glance I agree that the RAAP concept is meant to capture some principled institutional relationship between different cross-sections of society. I might disagree with "The Narrow Corridor" argument to the extent that RAAPs are not meant to prioritize or safeguard individual liberty so much as articulate a principled relationship between markets and states; according to RAAPs, the most likely path to multi-polar failure is particular forms of market failure that might require new grounds for antitrust enforcement of AI firms. The need for antitrust and antimonopoly policy is thus a straightforward rejection of the idea that enlightenment values will generate some kind of natural steady state where liberty is automatically guaranteed. I develop some of these ideas in my whitepaper on the political economy of reinforcement learning; I'm curious to hear how you see those arguments resonating with Acemoglu and Robinson.
Agent-agnostic is meant to refer to multi-agent settings in which major decisions responsible for path-dependent behaviors are better explained through reference to roles (e.g. producer-consumer relationships in a market) than to particular agents. In other words, we are looking at processes in which it makes more sense to look to the structure of the market as a whole (are there monopolies or not, where does regulation fit in, is there likely to be regulatory capture, do unions exist) than to look at what particular firms may or may not do as a sufficient explanation for multipolar failure.