Traffic patrol results in revenue for the state. Theft investigations only result in costs.
True story: when I was in my first year of grad school, working at a Wal-Mart, my car got broken in to in the parking lot while I was at work. It was the day after Christmas and I had just come back from my hometown and hadn't even had a chance to stop at my apartment and drop off my stuff. Luckily, it was all in the trunk. However, my discman, cassette adapter, and a case full of CDs was in my passenger floorboard.
Someone bashed the window and made off with the CDs and electronics. The total amount of the items stolen from my vehicle was over $500, making the theft a felony. I called the cops, they investigated, and a report was filed. A week later, a theft ring was busted across the border in Iowa and I saw some of my stuff on a table in the news clip they aired about the bust. I went down to the police station and reported this. Their response was "If you want to drive over there and find out for us if it was your stuff and then let us know, we can go ahead and call this case closed." I ended up finding about half my CDs for sale at the used record store in town. Even though I had put my initials in the liner notes with a Sharpie, when I told the cops the CDs were at the store, they wouldn't even question the owner about where they came from. Now THAT'S public service, right there.
Here's hoping your cops are better.