It doesn't work like that anymore Remy. Any OC with a scintilla of offensive proficiency gets a HC job. You aren't going to keep an offensive staff intact for very long unless its the HC's system.
Greg Roman has never been a HC.
If an OC Quinn hires gets a HC job then that likely means they were successful developing Fields. That should also mean Fields would have the tools to succeed without them.
If you are telling Fields can only succeed with this one OC then it means Fields is not a franchise QB.
Just doesn't mesh with Poles allegedly saying "all Fields needs is weapons around him", and you want to take a look at a failed DC candidate in Dan Quinn? If you want to weaponize Fields you would think that hot OCs like Daboll, O'Connell or even Hackett would get a look.
The GM ie Poles is responsible for getting him the weapons not the HC. You are really wildly speculating based on your own bias.
Is it possible Poles wants a HC that can be focused on being a HC because he wants the OC and QB coach to have the bulk of their focus on Fields?
Perhaps that is why he is interested in 2 DCs and a former OC who has already said he will not call plays.
Daboll may be great as an OC but as a HC he may struggle to be able to call plays while developing Fields while still doing all the other things a HC is responsible for. He could focus on Allen in Buffalo because someone else was HC.