How do we know? He never had been a HC.
My point is that success as a coordinator does not always translate into success as a head coach. There are different skill sets involved. If Chief doesn't recruit well (I've heard that others did that part of the job for him) and isn't a good manager of personnel (don't know about this aspect with him), he probably wouldn't be a good HC. With his track record at coordinator, you would expect him to receive offers if Athletic Directors valued his skills in those two areas.