I think that's more to do with the role of head coach, is it 'coach' or is it manager. Vince Lombardy said coaches that can explain a play on a chalk board are a dime a dozen.
Many assistants are basically cone fairies. They have expertise in a small area but have nothing beyond and act under direction. Every coaching course I have ever been on is about skills. At this level you shouldn't be coaching a player skills they should already have them. Head coaching is about management, until there is a proper coach development pathway in place this will be a constant argument.
Top flight football coaches of all codes (except NFL) get their jobs in this age through one thing show us your medals. The belief that you cannot be a good coach if you never played at the top level needs to be shaken out. Who the fuck let Sam Burgess become a coach after 5 mins of retirement? you could go down the local club on a sunday morning and see people with 10/20/30 years coaching experience who would be far better. The simple reason you don't get them at the top level is nobody has heard of them.