I worked for a brilliant but ruthless businessman at one point in my career who very openly "stabled PhDs" (his words) in the field (RF engineering / DSP). He'd

I worked for a brilliant but ruthless businessman at one point in my career who very openly "stabled PhDs" (his words) in the field (RF engineering / DSP). He'd give them some research projects to play with for years on end just to keep them away from the competition.