Sure, lots of Head Coaches were hired with no HC experience. However, they usually have years of experience being Coordinators and calling plays for their side of the ball, and over time, they pick up the nuances of proper game management. McDaniel has no experience in any of that... absolutely zero!
IOW, anyone who would hire a guy who has never run anything at any level, and not only make him the HC but also allow him to run the offense and call the plays, something he has never done, can't be too concerned with winning.
You keep mentioning profits, but as I said, all owners are making money whether their team is a winner or not. I'm sure that the team is worth a lot more now than it was when Ross took over. From my point of view, he's collecting his money, and he's putting money back into the team and stadium, but none of that is contributing to making the Dolphins a contender because he refuses to fire an incompetent GM and a HC who can't even get plays called in on time.