Yeah, I get it. I was mostly joking, but a few things:
I strongly suspect most people buy either the official case from the manufacturer or maybe they go to Amazon or buy one from their local store (Best Buy, Verizon, etc.). They are high markup items and thus readily available in places people shop already.
I find secondary markets that are essentially universal interesting. Imagine selling a TV, but not including a remote control, that seems absurd. What I strongly suspect is happening here is that the market does not favor phones that don't need cases because people want to buy cases. When you're talking about toting around a generic black rectangle everyone else has, there is a desire to make it unique and expressive through the case. I think even with plastic phones, cases would still sell.
I go through several cases and screen protectors during the lifetime of a phone. If the phone was made of the same materials as the cases, I'd either be looking at a new phone each of those times, or putting a case on it anyway.
