TD is preparing for the playoffs. When SA has failed in the playoffs, it is because his teammates have not been able to help when he was more or less equalized. TD is playing just well enough to make the team great, but he is allowing his teammates to do more, so they can be ready in the playoffs, and carry the Spurs when his game is off.
This is a sound strategy, IMO. Guys like Manu, Beno, Rose, TP, Bruce and Barry are all getting more and more confidence because they are helping more on offense as well as defense. This will lead to a better more well rounded team come the playoffs.
This is something DRob did not have the luxury of doing.