You have correctly identified the heart of the problem, > to explain and simulate the human economic interactions with less energy than required to just run it

You have correctly identified the heart of the problem, > to explain and simulate the human economic interactions with less energy than required to just run it with real human I think we have become mystified by the type of "engineerable reductionism" that very modern science has enabled. This religion of "engineering approximations" has taken the popular imagination captive, academics included, and has led to people being extreme reductionists. As an anti-dote, I think we should consider problems which are physically impossible to compute; interactions which require infinite energy to measure; simulations which take the age of the universe to run. We find problems of this kind everywhere and they out-number the solvable ones infinity-to-few. We cannot compute the shape of a table from the positions of its atoms (10^30 states) let alone human behaviour from god-knows-what (the state of some neurones, ad prices, or blood flow). In the face of what cannot be known either in principal, or ever in practice, we should resist engineering solutions. I dont think there can ever be a reductive science of human behaviour. We are in exactly the position almost all humans in history have been to matters such as chemistry: unable to make any pronouncements whatsoever. I think in the case of "the hard problems" in irreduibly complex cases, we should wholesale reject the reductive scientific method. It can only lead to pseduoscience. We should instead be extremely careful and locally theoretical empricists, as the anchinets. And say only, "over here, this happens", and "over there, that happens". And so on. Any more is charlatanism, delusion -- and worse -- an invitation to the public to a superstitious pseudo-scientific religion.