I have had managers fail in the past for different reasons. Both were promoted from a team leader position, where they were responsible for carrying out assigned tasks, staff scheduling, and work flow. Once they became managers they struggled for different reasons.
One couldn't follow through on projects and tasks. She would say she "forgot". She was often overwhelmed with the amount of requests and operational issues coming from different areas. Many things fell through the cracks and she eventually went back to a staff level position. She was very good at completing tasks if there were clear instructions. She could not foresee the things that needed done or addressed without being told.
The other example I have was also someone promoted from a team leader position. She was great at completing tasks, could handle projects and follow through but could not hold staff accountable or have difficult conversations. She wanted to be friends with everyone and blamed me or HR for the rules. She did not lead her team through change by explaining the reasons for changes and helping her direct reports see the big picture and how it related to regulatory requirements or the organizational goals. She didn't "walk the talk" and wondered why no one was behaving the way they were supposed to. If a manager is not willing to lead a team in the right direction by supporting the policies and procedures they won't be successful at leadership.
Discussion Question 3(My Professor Asked)
Rhonda & Class--I have had managers fail in the past for different reasons. Both were promoted from a team leader position*** Sounds like cases of the Peter Principle in action. In addition to the Peter Principle--there are a couple of other principles you should be aware of--the Dilbert Principle and the Nartreb Principle. Check out the links below--have you seen these principles in action? What are your thoughts on these principles?
USA 
India