I haven't seen a coach yet who was so good that he really “could take his’n and beat your’n, then take your’n and beat his’n.”
Similarly, we have seen all too often what happens when you have a fairly talented team coached by morons.
One juggernaut dynasty was completely shredded because of a total goober as HC.
We had a very high level of talent from 2007 to 2009 and went nowhere. Jason Garrett had teams win 12 and 13 games and go nowhere. McCarthy had enough talent to win 12 games three seasons in a row but ultimately went nowhere.
Jimmy Johnson or coaches like him would have been in multiple conference championship games and probably had won a super bowl or two with the same rosters those clod coaches flopped with.