Remember in "Life of PI" near the beginning, where it says that an animal in a Zoo will happily stay in its pen as long as it has its needs for food etc fulfilled.
When they do try to escape it is not because they are looking for something better outside. Something in their pen makes them uncomfortable or frightened and they are trying to get away from it.
The people who leave are unhappy or uncomfortable. As long as the Gibbering buddy thinks that beating the sheeples will improve morale the bleeding away of members will continue, and accelerate.
HB