I detect sarcasm here. Hmm.

Naw couldn't be.
As others have said, his core has been kept in tact at various times. The highest turnover rate is from the bench players, the guys who were good first rounders that didn't pan out with the clubs that drafted them. Of course he couldn't evaluate them until his coaching staff worked with them in practice and game situations. That's the nature of trying to find gems like Raja Bell for instance ...
I know you think you proved something with the stat, but I don't really think it's that significant a number over 7 years with an aggressive GM with a firm idea of what he wants. Many here don't like his vision, but it is a very definite one. It may not work, but it's by no means wishy washy. He is aggressively seeking out the kind of talent he thinks his team needs. He likes a mix of team-oriented players with diverse/flexible skills and athletic players who will attack. His biggest change came when he finally acknowledged that his team needed a defensive leader in Casey, who had roster requirements of his own.
It isn't always black or white.