Cini is right, the manager makes a huge difference. There is a big difference at winning a few domestic cups with a big club and resources of Arsenal than being title challengers against the very best. He hasn't been able to get his players to consistently perform for over 10 years now. If a manager of a business or a teacher of a class fails to get their employees/pupils performing, who's fault is it? Can't see the shareholders or parents blaming the staff or their children can you? So why is football any different when it's result and profit based?
What about when fergie left, I don't recall anyone blaming the players when Moyes flopped. What about Sherwood for Spurs? AVB for Chelsea? Soon to be Conte? The list goes on mate.
If managers get sacked for less, like Conte is soon to be by the looks of It, why hasn't Wenger? Yesterday's performance highlighted the gulf between the teams, not because of the players but from the managers own doing.