This defending merits the sack

Our defending has not been good enough for years and it is clearly the manager's responsibility to send out a team that can defend adequately in order to have a good chance of winning trophies and football matches. The manager has had years and millions of pounds to sort this problem out. Nothing seems to have changed, the same mistakes keep on being made and it continues to cost us points and trophies. The manager continues to say the same things, acknowledging that we have big problems:

"You cannot say you are not worried when you see the performance we put in today. It's just not defensively solid enough. When you are 2-1 in front against Blackburn and you know that you are solid defensively, we will score goals."

Personally I am finding it harder and harder to listen to these statements of fact. We have a defensive problem and we have had it for years, why on earth has it not been addressed? One man has to hold his hands up for this and take responsibility for it. I am a massive Arsene Wenger fan, he is a lovely human being, as well as a highly intelligent and articulate football manager. There is only so long that devoted Arsenal fans such as myself are prepared to put up with this situation and it really hurts me that things have gone this far. It feels like I am cutting into myself with a rusty knife as I write this but I am starting to feel that if Arsene were sacked now, it would be a very justifiable decision, his position is bordering on the untenable.