You will notice that steel guitar pickups are generally wound with more turns and higher DC resistance and the bobbins are moved closer to the bridge to retain the treble associated with more turns. Some steel guitar pickups are wound over 10 k Ohms and with the increased turns, you loose the high-end and it would sound dark if used further away from the bridge as guitar or bass pickups. More turns are used to increase the sustain and output as the pickup is moved closer to the bridge where there is less string vibration and to retain the treble.
Again, many other styles of guitar pickups can be used for lap or steel guitar when used with a slide and the volume and tonal variations will change with what is being used.
WRITTEN ON JUNE 12, 2015, BY