Better funded departments are starting to test them out, but the demand from local police still isn't quite there. They require obtaining a special FAA license and lots of training, which makes the sales cycles on drones long and unattractive to vendors selling one at a time to local PDs.
Still though, their pitch is: "A helicopter flight cost is $450/hr. A drone is $14." Saving PDs the cost of flying a drone to/over an accident scene is more the draw than snooping into buildings.