I used to think these kids get into gangs and crime, because they lack a positive male role model in their lives. I assumed they were all from one parent families, living on rough, inner city estates.
The reality of it, is many of these kids are from two parent families, who work hard and are law abiding. Often these parents are completely unaware of what their children have been doing, as at home, they are the model child.
I don't know why things are like they are anymore. Peer pressure seems to have a strong hold on the outlook of these kids, so much so, perhaps losing face with their fellow gang members is a greater sense of shame, than actually taking someone's life.
I have no idea what happens in schools these days, I've heard they do send youth workers and community police in to talk about knife crime. Children need to be taught about empathy from day one and bear the consequences of their actions.