Who is the last great player who became a great HC?
I can't think of any, but I suppose there's been a few.
Point being that the job of HC is a unique job. An HC is not about being a great OC or a great DC. It has to be about leadership, the ability to motivate, strategy, an eye for personnel, discipline, game planning, teaching, communicating, getting the most out of your people (players and staff), adapting to situations both on the fly and longer term as injuries occur to key personnel and the game rules change.
I simply don't know how it's done in football to find that successful HC. Clearly the usual path is that a DC or OC is elevated, sort of like "working your way up" the organizational chart. Sometimes HCs are lifted from the ranks of position coaches, even STs coaches.
They come in all sizes and shapes; guys who played the game and guys who didn't. Younger, older, introverts, extroverts, emotional, stoic, etc.
I still think it is largely a crap shoot and finding that right combo of owner, GM, and HC and hitting on some picks at the right moment at the right time.
Tom Brady made Bellicheck as much as Bellicheck made Brady.
If Bellicheck is smart, he'll retire when Brady does.
I wish Demoff and the Rams the best of luck.....because the older I get the more I see that luck plays as big a role as the art of evaluating the person.