I just thought of an analogy that I now like for the change(s) that are coming
You've heard of people doing home renovations that are "down to the studs"
Well-- and most of you probably know this already-- but the vertical studs in your walls rest on horizontal beams (in the roof they're called rafters). The two facing walls that the beams end in are the load-bearing walls, and the two walls that are parallel to the beams (and perpendicular to the load-bearing walls) are non-load bearing. These horizontal beams, in turn, rest of vertical posts that transfer the weight of the building to the ground.
Now, If you house has structural damage you gotta replace everything that rests on/transfers weight to the most load-bearing thing that needs to be replaced. So if the studs gotta be replaced, you gotta replace all the walling material and the systems in the wall that are supported by studs. If the beams gotta be replaced, well all the studs will have to go, too. If your posts have to go, well so do all your breams, at which point most everything that is recognizable as a 'house' is gone and you're more or less at a full demo.
Anyway, I think something similar works within the staffing set up of NFL teams, and especially the assistant coaching staff, the HC, and the person functioning at the GM. If the HC gotta go, you should be prepared to lose all the assistants. If the GM gotta go, be prepared to lose the HC. Whatever level is getting replaced you can't expect to salvage the people who report up to that level.
This has been brought up from time to time, but it's one of the mistakes the Bears have been making the decade or so. They keep doing this in the opposite order. So whoever is the GM didn't pick the HC and whoever the HC is didn't pick the QB.