I have a tendency to look at it like the offense is a spoked wheel. Where the QB is the hub of the wheel, and all of the other players are the spokes in the wheel. If the hub is faulty (Manuel, hub under fabrication still) in any way, then the spokes can never be trued up (alleged locker room dissatisfaction with Manuel). It will be a rough ride.
On the other hand, if the hub is in good working order (Orton / Manuel swap), then you can start to true the spokes up (chemistry, trust). As each spoke gets trued up, the ride will begin to smooth out (the current status of the offense, everybody seems to be behind it). Everything revolves around the hub.
While I agree with you that it is a team effort, I feel that the majority of the responsibility rests with the QB.