Here are the factors that really helps the Spurs to developed their players.
The Spurs were early on the scene since with drafting international players in the 90s. This has been huge for their dominance starting in the 2000s up until now.
Coaching staff has taken regular trips overseas to see and meet players early in their development. Doesn’t hurt that Coach Pop can speak more than English. RC Buford and other also great.
Team has an incrideble network of former players, scout and coaches through the NBA and overseas by which they can gather information.
Have been able to draft and stash international player overseas and bring them over when they are ready. Not all have been a huge winners but many had a decent careers whether with the Spurs or elsewhere. Just consider Manu, Tony, Tiago, Ian, Beno and Luis. Plus there are still some young nice picks stashed overseas that could make their way over to Spurs team in future years.
Whether picking early or late in the draft they have tended not to worry whether the person could help them immediately or not. They have taken the player with the most upside even they cost them in a short term.
Consider David Robinson whom they didn’t know when to get him due to Naval obligation. They believed he is the best player for them to take and took the risk that he would join the team sooner or later.
In trading George Hill to move down to take Kawhi Leonard they took the big picture into consideration giving up a very solid player who was loved for the potential upside of a guy at the time according to Pop, could possibly be the face of the franchise down the road.
They avoid drafting players with heavy baggage, bad attitudes, chronic patterns of poor choices, poor work ethic, etc.
They take the best player available that can help them win where the NBA heading at that time.
It’s start with Pop and the humility he and his staff instill in the players.
Nobody is above guidance, correction or a good chewing out including current and past stars like Duncan, Robinson, Ginobili and Parker.
Pop never takes the credits he talks about the team and the players making it happen.
Then as new or young player on the team what attitude are you going to put out when Duncan just reamed out and took it.
The Players are so professional they self police the younger guys they really want to win no just to collect a paycheck.
Management has been incredible for retaining a great coaching staff and not meddling with the program. So you have stability which help players.
The Spurs invest a tremendous amount of time and resources to develop young players.
Popovich is willing to adjust the game plan to the strenghts to his personnel which help almost everyone to develop.