People in leadership roles (not necessarily good leaders, however) have egos. They've gotten to the level they're at because of their ability to get things done. Many times, this is a specific, technical skill (e.g. sales prowess) that has helped them get promoted.
That ego, created by their technical proficiency, often gets in the way of empowering people to do the best they can do their unique skillset. Humility and the ability to clear obstacles rather than being one is a key to getting an organization aligned.