I think the one common cause that can be identified in the slow descent into anarchy that is Britain today is the wiful removal of individual responsibility by a State that seeks more and more control over our lives. When you become more and more detached from controlling your own life, a culture of both entitlement and powerlessness is created.
Hence there's a reluctance to confront someone being a plain nuisance, let alone anything worse, because The Authorities will come down on you like a ton of bricks for interfering. Hence you get thugs thinking they can just steal whatever they want because they've no respect for other people or the work they've put in to get what they have. Hence the mollycoddling of our young and their resultant belief that they need show no respect to anyone, but that they have the right to deal with as they wish, those who they perceive to have disrespected them. They're right too, given the hand-wringing that goes on on their behalf, excusing their behaviour as a result of poverty or boredom rather than plain despicable actions and giving them less than a slap on the wrist (that would be child abuse...)
When our actions and their consequences are separated to such an extent, is it any surprise we end up in this mess? Still, the death penalty would only assuage our desire for revenge rather than actually improve things.