Achieving a cultural change is simple, not easy. Simple because the fix consists of watching patterns of behavior for a while, identifying the cliques of users

Achieving a cultural change is simple, not easy. Simple because the fix consists of watching patterns of behavior for a while, identifying the cliques of users who do this, and then mass-banning them, or at least mass-revoking their privileges to close stuff. For maximum cruelty, just reset and peg their reputation permanently at zero. Not easy because then they're going to scream their entitled little heads off about it, and you'll need to recruit another generation of active moderators.