I remember listening to an interview with Willie Sutton after he "retired" from bank robbing. One of the keys to his "success" was that everyone in his operation got the same amount of money, e.g. the driver got the same amount on stolen money as Willie received. His reasoning was that no matter their involvement they all had the same risks and it reduced jealousy. He also respected his "gang members," so it was relatively easy to recruit the best in the business. He made a point of saying that when it all comes down to it, running a successful bank robbing enterprise was just like running a business: plan well, hire the right people, respect your personnel, and ensure everyone is rewarded.
BTW, he never killed anyone in all of his robberies. While he carried a gun, or a Thompson submachine gun, it was never loaded. As he didn't want anyone to get hurt. 🙂