
everyone quickly pointing fingers thinking about the question seriously. The
true, and only, factor that led to the Spurs' current irrelevance is.... The NBA system itself.
Tell me which of the 30+ NBA teams have managed continued, unbroken, permanent relevance through the years - I'll wait. The fact is, no matter how high the highs (and there certainly have been dynasties and superteams for days throughout the NBA's 75 years), every single team that once dominated, has seen the "turn of the wheel" and, with it, the eventual drop to the bottom. Players age, the wheels fall off, talent drought, and the human factor of course - literally not a single team has managed to avoid it. Not the Celtics, nor the Lakers, nor the Spurs.
But of course, the Spurs should be singled out and excruciated for it, nevermind the 20 years of sustained excellence they've gifted to their arrogant fans. It's a "what have you done for me lately" kind of league, after all.