Because most engineers don't want to spend 6 hours a day in meetings to sync up with the rest of the org and get all the proper context and figure out politics

Because most engineers don't want to spend 6 hours a day in meetings to sync up with the rest of the org and get all the proper context and figure out politics and learn intimate business strategy and so on. Moreover decision by committee tends to not lead to the best results which means you in the end need someway to force a decision that not everyone likes.