Freddie Ljungberg hints at the equation. From the Daily Mail:

Ljungberg, who is currently a free agent, stated Dein had a big influence at the club before he left his position in 2007.

Ljungberg said: ‘One thing for me when I was there was David Dein, he moved between Arsene and the board to make sure there was money to buy new players and put pressure on the players that were there. I think there is a connection between when he disappeared and that we have not won a trophy.

The former Arsenal player and Swedish regular joins several former players like Emmanuel Petit (who said Wenger ‘lost’ the dressing room) in evaluating the current situation at the North London club. The Dein question is an interesting one.

Dein’s exit did feel at the time like a sea-change at the club, but most believed history, resources, and Wenger’s stewardship would carry their success forward. While Ljungberg’s assertion that Dein was integral to buying expensive players per se does not exactly chime well with Arsenal’s net transfer spending over entirety of Wenger’s reign, but he may have been integral in securing players of a particular quality, seeing as he was responsible for the wider share of their most storied recent players.

As for Dein’s motivational skills, we can only speculate. Nor is it perfectly fair to say Arsenal were not already on the decline before Dein left, although Arsenal’s appearance in the 2005-06 Champions League final seems like the stuff of dreams in comparison to the squad that lost 4-0 to Milan. But football is a game of good chemistry, despite the myth of the miracle-weaving gaffer. It could be several years before the historians wonder whether Wenger would have been better off begging on his knees for Dein to come back.