Nice post, but can't really see the point in it. Maybe I'm just being stupid, but I can't really see how what you're saying invalidates making a comparison between a RL supply and demand model and the games. I'm not an economist (just a mathematician ) but to me, in RL, more supply = lower prices (assuming same demand). In game, the same. Other side of the coin, more demand = higher prices (assuming supply doesn't increase). I can't see how this is different from RL and AO. As I said, not an economist, never studied supply & demand, but my extremely limited understanding of it is based on those two facts. Nothing in your post really changes that view. But a nice post anyway.
As far as I can see, the stuff about luxuries is just a red herring as far as I can see. One mans luxury is anothers necessity. It's all relative.