The reality is that their is a shortage of qualified men. I have seen that it is much easier to stay an Elder than to become qualified to become an Elder. It is structured corporate style. The CO's do not want to have much of a headache and that's why they are reluctant to appoint and reluctant to remove as both require action on their part and they could face being removed if they make bad choices. (Imagine being on the road for 30 years and having no income or retirement to speak of) They are going to ride that gravy train as long as they can.
There is no holy spirit directing these ones, it is all Egos and Corporate Policies.