Given DJ's hiring of assistants, it's hard to say that he himself isn't in a vacuum. (Actually, I think he knows people but they don't want to work for him and/or take the massive pay cut to do so.)
All the more reason to ante up and bring in someone like Schottenheimer, who knows how to build a football team, knows how to win and get a team playoff caliber, and knows everybody in the business. You're correct that adding more incompetence to the mix and stirring it with a spoon is unlikely to help anything.