I think you should have sought remedy in the civil courts. For $20 (or whatever), you probably could have at least gotten a default judgment against the guy and sold the case to a collection agency.
It does feel like in cases like this the cops rely on people having insurance and thus generally don't bother unless the break ins become an epidemic.
It's possible I could have approached the cops differently and received better success. Be more persistent? Be less persistent? Have a lawyer speak with them? I have no idea. When the cops refuse to do their job for whatever reason, there's no fool proof way of reversing that.
EDIT: And also, I probably should have been there when the cops came to the store. That might have also helped. Live and learn. At the time I thought "photocopy of the driver's license! score! I'm saved!" and was pretty naive about the whole thing.