Yes, Brad is an outstanding coach, but he likes to coach "underdogs" and "underachievers"! Guys like Phil Jackson and Pat Riley were hailed as top five NBA coaches in history, but they also only accepted coaching jobs for teams that were absurdly stacked. They weren't gonna coach those teams and players to championships, they were just gonna stay out of the way and let incredibly talented teams win. I really don't think BS would go for a job like that!
Yes, as posters have pointed out, he'll get you to the playoffs every year, he just won't win it. Now is that mostly his fault (I believe, yes) or Dannys' fault for not getting enough talent? We'll never really know, but like I said Brad has a whole lot of input on player acquisitions. Without superstars in their prime and veteran talent to put around them we're waiting for a train don't come!