"Unfortunately a lot (not all) of public authority managers are not very good managers."
I have had the good luck to work with some very talented and hard working staff in local government, but there are the a percentage of slackers and incompetant managers.
However, a big problem in the public sector is over promotion and lack of training.
For example, an EHO (the guys that make sure your food is safe) tend to be inteligent, well educated and motivated.
Because they where a good EHO, they get promoted to head of food hygine/safety, managing the team. AND GET NO Management training, but they know the job so they cope.
Because they did well as the team manager, they get promoted to division mangement, including stuff they've never done before, AND GET NO management training.
If they do well as a division manager, they get promoted to Director, with a portfollio of departments ranging from Food Hygine, to Highways, Planning, and Waste Management, and still get NO Management training.
If you are lucky, they will learn delegation, and have enough self confidence to rely on the subject matter experts that work for them, and not try and micro-manage or set policies on things they have little understanding of.
This is also try in the NHS, where you can get very good nurses, and they end up over promoted to running an entire hospital, and get no mnagement training or mentoring (result good patient records, and poor accounting and stock controls)