That's certainly a part of it. But, it has happened at center and guard too. The other really 'famous' one being Mustipher.
I don't know, I'm not going to pretend to be any sort of OL coaching guru. It just seems like the Bears really struggle with blocking assignments at times and their communication along the line. Like at the beginning of the season when they could not pick up a stunt, etc.
It'll be an interesting question for any HC candidate: Who is your preferred OL coach and what is their background to think they will be successful?