What happened to Arsenal's season?

A few weeks ago Arsenal were looking forward to the Carling Cup final, Champions League knockout stage and were still in the FA Cup. They lose the cup final, get knocked out of the FA Cup and Champions League and then just to cap it all off they get a 4-1 hiding at Anfield.
So what has gone wrong? How have they ended such a promising season trophyless? I would have to blame a lack of on-pitch leadership, they only have one player who shows any kind of leadership - Gilberto Silva. The problems really show when he is forced to play in defence or is absent completely, such as in the Liverpool defeat.
Arsenal were crying out for Gilberto's ability to break up attacks when Liverpool went forward. For all Cesc Fabregas' and Denilson's ability on the ball, they are weak when the opposition has possession. In time, with the right coaching, there is no reason to think they will not improve that aspect of their game. But right now they just need to build up experience to improve their positional sense and their ability to read a game's defensive aspects.
Though the Gooners do already boast a ready made replacement for Gilberto Silva in Mathieu Flamini. I was shocked to see Denilson given the nod over Flamini against a Liverpool side who boast one of the strongest central midfields in Europe. Whichever two or three of Gerrard, Alonso, Mascherano and Sissoko Benitez chooses to employ, they are a match for any team.
Arsenal were bullied in midfield to such an extent that they were unable to play their usual free-flowing attacking football. I think Arsene Wenger has been suckered in by the myth that Man Utd won the league with a bunch of kids to such an extent that he is trying to match that feat. The problem is United did not win it with kids, they won it with a combination of youth and experience. People forget that Schmeichel, Bruce, Irwin, Pallister, Ince, Cantona, McClair and others that I forget, were all experienced players that could in no way be termed kids. Arsenal just need to add experience to their game, whether that is through giving their youngsters more time or by buying it in only Arsene can decide.