Edelman says Dein was the missing link in Wenger's management team.
"During the years we were successful there was an alliance of people at the top who made the club successful - that was David Dein, Arsene and myself," he told the Mail on Sunday. "I ran the business side and David and Arsene ran the football side. David did a phenomenal job for the club and I think they miss David's role in encouraging Arsene.
"Arsene is naturally cautious and David was always very ambitious for the club. Look at Sol Campbell and how important he was and how expensive he was as an acquisition at a key moment when he won us a lot of trophies. [Campbell signed on a free transfer, but his wages and signing-on fees amounted to about £6million a year, at the time an unprecedented commitment.] I don't see that now.
"David was also a great networker. Together with Arsene, David would look at players and get into a position where he felt comfortable [spending money on them]. I used to sit in the boardroom and hear Arsene say, 'If you want to win the Premier League, you have to have a world-class goalkeeper'.
"Well, if that's what he believes, has he actually delivered that? David's importance is probably underestimated as he would make sure we now had a world-class goalkeeper.
"The demise of David is probably the reason why [Arsenal have not won more trophies], that and the fact that they haven't made some key signings at some key moments.
"There needs to be someone to understand the management that you have and to encourage them in their weak points and support them on that. Arsene is a naturally cautious man and, like any manager, he always thinks that his current management team is better than they actually are."