Well, you're right that it's an econ 101 thing - because it's not a grad-level econ thing. Real economists understand that the real world differs from those sim

Well, you're right that it's an econ 101 thing - because it's not a grad-level econ thing. Real economists understand that the real world differs from those simplistic models, and have (or are working on) other approaches that better model the real world. It's just like in Physics 101 you're dealing with point masses on a frictionless surface. Later on you learn abut friction and inertia, and still later you get into relativity. We frequently start with that simplified view of the world, but there aren't any real professionals who believe that's the end of the story. Markets do exist, despite the fact that your assumptions don't hold true to varying degrees.