There's a loser mentality that has been created at the club over many years, there have been no consequences for being shit at your job. We hire failed coaches, give them big contracts, don't sack them after performing abysmally. We keep failed players at the club to avoid having to replace them, we give long new contracts to players that have been performing poorly for eons, players can fail for dozens of games but keep a regular place in the squad while the transfer windows go by. Pundits and journalists talk about the pressure of playing at SJP, but if you ask me there is no pressure, where's the pressure on Gouffran or Coloccini or Colback? I'm sure it will be the same throughout the club, not just on the playing side. The club is full of losers by choice, and if a player comes here with a winning mentality, as someone like Mitrovic has, well that will soon be drained out of them by the environment.
This isn't McClaren's fault, but he's not the man to change it in a million years, he doesn't have the authority, track record, reputation, or talent. He's just a blancmange.