I agree with your initial paragraph but not your last one. IMO had Belichick been the Ram's coach he would never have given up what we did to get an aging Stafford. He would have kept Goff and gotten a far better QB coach knowing how Goff could be playing like he is today. Simply put I think we would have won the same SB with Goff under Belichick as they did but would be far better off today than they are now. We really could use all those draft choices given up and be better for it today. Of course was the Stafford/Goff trade all on McVay or -as I suspect-more on upper-and I mean WAY upper-management.
McVay is most certainly no "moron" and is likely held out by experts to be a good coach but he is predictable and innovative and has a good memory but that doesn't translate into one of the "greats".