Yeah this is true. The main issue is what Dan Quinn did in Atlanta after he lost Shanahan. He took a prolific offense hired Sarkisian and let him install his own system. Instead of using an offense that allowed Matt Ryan to continue playing at an MVP level, he let some other guy run his system. It's on the coach to be accountable for making sure he keeps that stuff consistentWhen you have a head coach with an offensive system ala Andy Reid, Sean Payton, Sean McVay, Kyle Shanahan, Bruce Arians, Doug Pederson, and Frank Reich, you never have to worry about disrupting your offensive system if your coordinator walks out the door for another opportunity if you are successful because you already have your coordinator built into your head coach.