For starters, they’ve asked Vegas oddsmakers how much a head coach is worth (Belichick) and it’s less than 7 points for an entire season. That’s less than half a point per game. Coordinators are much more negligible. Odds do not even move fractions of points.
Empirically listening to talking heads and fans talk about coordinators is a laughable exercise and full of confirmation bias. Rarely do these guys make a difference over a season. The QB and the players are the total output. Seen this so many times with QB so and so and how a new OC is going to “get the most out of him” and it’s the same result. And when there’s a great young QB the coordinator gets a lot of credit and then fails to replicate the results.
If you look at the NE offensive coordinators, the quarterbacks they have here, and what they’ve done elsewhere, you’ll see the light. It’s a whole lot of smoke.