The Spurs are one of the few teams in the league who avidly seek foreign talent. Half or more of their players are non-Americans. Non-American players have teamwork drilled into them which fits Popovich’s no stars style. Of course, it helps that Duncan, Parker, and Ginobili were/are great players, but Popovich expects every player to forgo individual glory and play for the team. Contrast that with many of the super egoes on other NBA teams.
Cohesion overcomes better talent.