The original plan of equal division is flawed. Each robber has incentive to increase his share by killing a fellow team member. Once a member performs his job, he loses his negotiating power and value to the team.
The Joker plays off this conflict by instructing the robbers to take out fellow teammates once their tasks are performed. The game would be different if the robbers were a group and they repeated crimes together—perhaps an even split could be sustainable. But as the movie hints right away with the first backstabbing scene, this robbery will be a one-shot game.
The list of examples and analysis provides some critical insight into one of the many situations of the movie that has yet to be fully explored. Unlike the ferry scene where many bloggers and others incorrectly asserted that it was just a fancy prisoner’s dilemma, this one is ripe for fresh exploration and Talwalkar does a pretty good job analyzing the components of the game.