Saw a discussion on this on the TV this morning. As usual the "there's nothing for kids to do" argument was trotted out (though I would guess that the majority of them have far more in the way of entertainment electronics than I can afford). "Kids need youth clubs" was also used - it was a long time ago for me, but I can't remember anyone actually wanting to go to a youth club - they were far too uncool.
Call me heartless, but I also couldn't find much sympathy when they showed a shrine to a young girl who had been killed after I saw her nickname: "Pit Bull". (Apologies if anyone actually knows her and the name was ironic).
As to the main question, I can't see any simple solution - it's far too complex a problem.