Using a separate case still adds a lot more bulk than would be necessary if the protective layer was built into the phone itself. This is just yet another example of the unavoidable cost of modularity that people have been bringing up everywhere in this thread. And even the nicest and most expensive cases I've tried have never really been able to compare with my actual phone in terms of quality of material and design.

Yeah, absolutely. You can't buy a high-quality one if you want to.