100% Blame is at Wenger's door for the player he became. Too much freedom given to the players.
Funniest thing is the season he was banging in the goals was the one season he actually played like a true CM. Was defending, tackling, got forward at the right times and actually formed a true midfield partnership with Arteta.
After that season he decided he wanted to be goal scoring 10 and was never the same again.