It's a chicken or the egg Situation with the Spurs and their players.
Clearly one of, if not the, best run organization(s) from the top down in the NBA.
Aside from Tim Duncan, I can't say any of their prospects have been "can't miss" on draft night. Leonard is a great example--he dropped to 15 because he couldn't shoot.
So the Spurs taught him to shoot. And now he's an incredible bargain for them, and an essential piece to their championship run.
Danny Green... almost out of the league. Bounced around a few teams. Ended up on the Spurs, and boom, he's also an essential piece to their championship run.
That's the thing about San Antionio--they've consistently show the ability as a franchise to draft good players, and turn them into very good/great ones.