There's really nothing favorable to Kawhi's career to purposely hold out. That's where I think all the doubters are wrong. I think, in his mind at least, that he's honestly incapable of playing. Remember, he's sat out before with very minor issues that most guys would have played with.
My concern is that Kawhi might decide he can't go at all if he's not 100%, and in that case his career is almost over. I doubt Tim, David or Manu felt 100%, ever, after about 5 years in the league. Tim's knees were "degenerative". The Admiral's back was "degenerative". Kawhi may have to face the fact that he might not get back to where he wants to be, health-wise, and decide whether or not he can play with constant pain. If not, he'll be done. I don't think it's selfishness. I just think he's not someone accustomed to dealing with injury or playing through it. The aging process won't treat him well if that's the case.