Have you ever been a victim of a non-violent crime?
Loads of those just fall through the cracks of the system.
"solving the case" is mostly keeping all documented until they stumble on to something obvious, like already known perp having your stuff hidden in his stashing place while they go grab him for something unrelated.
In my city's subreddit, last week there was both a post complaining about the police not doing anything about a car break in, and a post complaining about flock on the front page.
People hate all kinds of things police do until they need the police to do something.
If you don't have video evidence the vast majority of non violent crimes go unsolved. How many manhours is a car break in worth, or a break in? Especially when the end result more than likely is still not enough to convict someone on.