Martinez got plenty of time and the team got worse the more he evolved it away from the Moyes era
Koeman was hopeless and destroyed the squad in one summer.
Unsworth was a caretaker
Silva wasn't great either - nice guy but lacking tactically
Duncan was a caretaker
Allardyce was an interim
Ancelotti walked to take the RM job
I'm absolutely not going to defend this useless squad of footballers, but did they really see off all these managers? Is it not the case that the managers, except from Ancelotti, are simply average managers at best?
My opinion is that everyone is to blame. The players are not good enough and lack fight and hunger. The managers have been poor appointments by and large and the only good one ditched us. The blame lies across the board, and the managers have been sacked for failure. Unfortunately you can't just sack 10 players in a summer after a failed season.