The process of hiring a director is performed by people who often know nothing about how a library works. Management is a different career field. A director may know little about the day to day operations of his or her library. They are not selected for their technical ability. This is often the biggest complaint from frontline staff. It is also why staff prefer to have their say in the hiring process of a new director. They would like to see the candidate through the prism of their own jobs and if they know more about them, they make the better candidate. This is not a true statement.
Management is about dealing with people. It doesn't deal with a collection, or the few minutes handling patrons, but the long term dealing with staff and making the library a growing organism. Everything is viewed in macro terms. What are the big needs of the community, how can we reallocate staff and resources to meet those needs. People on the front line will wonder why this is happening, why these changes are being made, and how much better things were before the change.
Frontline staff, middle managers, and directors can be viewed in different ways.
Frontline staff are like a triangle, heavy on technical expertise, but don't require staff management and are not required to look beyond the day to day. Often the viewpoint is, if it's not broken, don't fix it.
Great to have technical expertise. It is critical for the day to day. However, these particular skills don't translate into management. You might be able to order great books, catalog fast and efficiently, or think of great programs, but none of these particular skills translate into management. Hence, a particular library skill doesn't translate into management. Often this is the case as someone gets promoted based on excellent technical ability. Once they move up, they don't have quite the effectiveness since they are unprepared to go into a different managment field.
Middle management is the diamond shape. Deals more with people and managing the frontline staff.
Usually, dealing indirectly with the technical piece and more dealing with people on how to do something. Managing people resources to accomplish a major library goal.
The Director, the upsidedown triangle.