I think it's reasonable to believe that the Spurs' organizational culture isn't a great fit for everyone, and that some veterans would prefer a different vibe that more closely matches the rest of the NBA. That's fine, you can't please everybody, but the idea that the Spurs' culture hasn't been the driving impetus for their success is pretty far off base. First, no one likes being in a toxic workplace, and there is nothing that will drive any professional to leave an organization faster than a ty work/office culture. This is one of the many reasons why "culture eats strategy for breakfast" has become cliche in the corporate world. A good team culture helps put people in a position to succeed and thrive in the same way that a good office culture does, which is one of the reasons why the Spurs have been so damn good at developing and retaining elite NBA talent.
Here's a question I have for the anti-Pop brigade. Do you actually think that the Spurs could have possibly turned a bunch of 29th overall picks into a viable young core without Pop? Do you see the hit rate for most NBA franchises in the draft? It's atrocious. Boston has has like 1,000 first round picks over the past few years, and outside of their top 5 picks, most of those guys washed out of the league within a couple of years. The Spurs almost never fail to develop a draft pick into a good NBA player, and almost all of that comes down to coaching and culture. Guys like Danny Green don't just grow on trees around the rest of the league.