In accordance with the standard hierarchy of needs, culture flows down from compensation. When everyone's material needs and desires are well satisfied, they interact genuinely and naturally. When people feel like good compensation is difficult to achieve, they put more effort into zero-sum internal politics, maintaining appearances, and so forth. You see this in upper management all the time; execs are friendly and…
Execs might be congenial because at that level, congenial is just how you play the game. It's still cutthroat, but overt backstabbing doesn't get you very far in a tight knit group of execs. But in other groups like a team of devs, IME high pay just attracts the kind of person who wants even higher pay and will do whatever it takes to get it.