Personally I do not think too much blame should be placed at the door of Mr. Wenger.
I have a great deal of respect for him as a manager & the ability to spot young players who he then develops into stars.
The rot started when the Gunners decided to move to the new stadium. Wenger was told that, because of the development costs, there was no money for high value signings until the move was over.
So he had to get on with what he had, sell players once they reached the stage that they would blow apart the wage structure necessary to maintain the financial restrictions placed on him.
The fact that they managed the move with cash in the bank (& maybe because of the ownership problems) meant that they continued with a financially prudent approach even after the move.
The might not have won any silverware for 6 years but they have a financial stability that should be the envy of all. Indeed EUFA (hardly a pro-English organisation by any stretch of the imagination) have held the Arsenal financial model as something it would like all European clubs to aspire to.
Sadly the men with suitcases full of cash still win all the silverware & will continue to do so while the playing field is stacked in their favour.
The only real mistake that I think Wenger made was in not letting Fabregas go last season & compounding that with making him captain. To have a man who continually whines on that he wants away as captain is never going to be a recipe for success.
I wish him well at Barcelona & hope he gets enough games rather than ends up a spare cog in the same way that Adebayor has at Man Citi...
Many (probably all

) of the young players are manipulated by 'agents' who make a financial killing on a player who can complete as many big money deals as conceivable. Sadly that is another failing in the game that the authorities have had little success in solving.