I think it might be heading down the wrong path to talk in terms of "rational beings" as atomic units rather than in terms of energy (or rather information) balance.
Remember that you do live in a simulation of the universe so compressed it fits between your ears, and it does contain many simulations of other rational actors. They're nowhere near as complex as your whole universe, but I bet they're complex enough to know that they're complex enough.
I don't see how this philosophical argument is going to change anything. Each human has a rather small finite number of 'rational beings' they can handle processing at once. It doesn't recurse very well, the limit is a total. The exponential argument against simulation is unaffected.
Remember that you do live in a simulation of the universe so compressed it fits between your ears, and it does contain many simulations of other rational actors. They're nowhere near as complex as your whole universe, but I bet they're complex enough to know that they're complex enough.