The problem is finding any in good condition. Very few (if any) people take care of their games like I do, and treat them and their cases and manuals with the care I require.
I hear you. I'm the same way. However, I just make them give me a case & manual that are in good condition. They typically have a few copies of the used games, especially recent ones. The Otogi 2 I just picked up is in mint condition and still shiny! I won't buy any used games that won't "look good" sitting on my shelf. Obsessive? Yes.