Pop's locker room tactics have been correct. Of course Duncan's retirement impacted things severely. But having marginal players like Simmons and Dedmon playing for their own stats is incredibly corrosive. That's what transforms a good small market organization into just another Bucks or Kings, just a backwater of crap for ages on end.
Once Pop goes, I think the old regime will go, too, and there's little chance of the Spurs competing for anything. They were incredibly lucky to get Robinson, but then they had no secondary player who challenged him in terms of ego (Sean was a great fit). Duncan and Pop locked everything down. If you weren't in with the program, you had to go. Soon the Spurs will be just another wasteland.