This is no revelation to Ozzie Newsome who went outside to hire a new HC knowing he risked losing Rex in doing so, or to Thomas Dimitroff, Atlanta's new GM, who from his NE days understood coaching talent, and after interviewing Rex, went out and hired a less-heralded DC from Jacksonville as their HC.
Rex is a walking example of "The Peter Principle" (people rise to the level of their incompetence and remain there)
Wisdom from a "QB Whisperer::
"No we have our FRANCHISE QB and I want to keep him rather than get 2 guys who may or may not be productive NFL players.
Palmer's situation is different and if I had my choice between Palmer and buttfumble, I'd take buttfumble"