Scientific research focused on leadership is very well established and brings a wealth of serious knowledge. Most people, including those responsible for selecting and evaluating leaders, however, don't know about these scientific findings. That's the reason for low levels of employee engagement and confidence in subordinates.
A very common example of a misconception is the expectation that it's difficult to predict whether someone will be a good leader, because leadership depends primarily on specific situations. It's equally misleading to think that anybody can be a leader.