I do not believe all instructors do it just for money, some do, some just want to build experience and move on to bigger aircraft, but I do believe alot of them do it for the satisfaction of seeing people that had never flown before, walk out of the door, tall and proud, qualified as a helicopter pilot. Its a great and very rewarding feeling. Its similar to Richard Branson's old primary school teacher who secretly says to himself, I helped make that man successful, credit where credits due, he couldn't have made a fortune if he didn't know his times tables and percentages for all that profit.
Frank Robinson identified two important things many many years ago when he produced his first helicopters.
The first was that the inital assesments of accidents in his aircraft pointed to High time fixed wing, Low time rotary, as people being the most likely to crash his aircraft.
The second is that he always believes that it is not the experience or skill of the pilot that may cause the accident, but the attitude which the pilot has towards flying the helicopter.
Frank is right and pyschometric testing of students prior to starting training (and turning them away if they fail) is probably the best way of reducing the accident rate.