I normally wouldn't ascribe karma or anything like it to a basketball team, but I always felt like there was some sort of Universal give-and-take when it came to the success of the Spurs and even individuals within the organization. Take Bruce Bowen. In the Universe's system of meting out justice, maybe the only way for Bruce to be such an, ahem, effective defender is for him to pay for it with something else, like never winning Defensive Player of the Year.
For the team as a whole, it's become glaringly obvious over the years that they don't/can't/won't repeat as Champions.