Sure, desire has a lot to do with it. But so does lower body strength. I've long suspected that LMA just doesn't have strong legs and that's why it's hard for him to get deep position, and why he struggles to back players down, and why he can't jump over a defender to dunk the ball.
Kaman's offense is brilliant. He's far and away the best post player we've had since Z-Bo. Great foot-work, very agile, able to go either direction, can face-up and take the ball to the hoop, or back down and use spins and fakes to get clean shots. And on top of all that he's got good vision to be able to pass the ball when defenses collapse on him, or lose their assignment.