Suppose Bird decides that he wants to trade George and start all over with a new coach, new system, and new core. Let's also suppose that he'd rather help out his buddy Ainge than the hated Lakers. However, it still will take a pretty decent-sized offer to nab him.
Would you trade something like Crowder, Smart, Salary Filler, Top-2 Brooklyn Pick, and Dallas pick for something like George and Miles? That would give them a really nice core of Smart, Crowder, Turner, and Simmons/Ingram, along with two other first rounders that they might be able to package for a mid to late lottery pick.
George would be an excellent draw for Durant, and if you'd add someone like Horford at the 5, then you'd easily have the best front court in the NBA.