The short comings of his head coaching gig in Detroit always seem to overshadow the development of Matt Stafford at that same time.
Unless we ignore him going from this:
to this:
Him not being the best head coach doesn't negate what he is good at.
This also shows how standards are set differently for "reasons," but that's another topic for another day.
I didn't say the QB didn't matter. My argument has been building the scheme around the QB. Crap, everyone talks about Purdy ignoring that he is basically Jimmy G with a "stronger" arm. Look at both of them operating Shanny's system and the only difference that really sticks out is Purdy is actually willing the throw the ball further downfield (Jimmy G wasn't about that life..lol).
I agree with you to a point but we've seen too many QBs leave bad coaching/scheming/team/bad fit and become more successful. All of the things you listed are needed for success. But this goes back to the point I've always said. A great coach can make an "average" QB great. A bad coach can make a "great" QB bad.