Substantially true. I've been told that some items (high value, readily pocketed, to generalize) never seem to get turned in to lost & found. If you place any value on your time, forget it.

Now, if you had realized the device was missing while the aircraft was still sitting at the gate, you could have reboarded and checked the seat pocket yourself. (Admission: I have lost books on airplanes on five continents.) But once the plane takes off for the next flight, chances of recovery drop daramatically.