It seems more like a prisoner's dilemma situation, where hiring from an in-group only works if you trust other members of the in-group enough to return the favor. Otherwise they could "betray", hiring a better candidate from outside the group who will perform better in the role. The person betraying would get both a better employee and the social kudos of having a diverse hiring record. I'd expect the trust strategy is a lot more common among fraternities, religious groups, diaspora communities, etc where community bonds are much stronger.

I believe that's exactly the sentiment behind the term "race traitor."

And to restate your point, the business may gain greatly from diversity in leadership, but the in-group mainly stands to lose. If they don't stand to lose then it's not really power sharing, is it? In my experience, these efforts hit the wall the moment they seek any real piece of the power pie. That's the difference between talks-the-talk and walks-the-walk.

Do you mean diversity in race and gender? I thought the argument was that there's no differences between races and gender? I actually genuinely believe that everyone should be treated equally but your line of thinking seems to suggest race and gender matter in decision making, its contradictory.