It's best for the media to back off this question. The boy needs medical help, and that should be the focus.
Children are taught to obey adults and authority. Obedience starts at infancy. Reinforce that innate drive with physical violence and I can easily see how an 11-year-old would not call home.
I also think that just being abducted proves to the child that the abductor is stronger and/or smarter than the parents and are able to out do the parents when it comes to the childs safety. As time goes on and the child is not rescued -- and don't children think it is the parents who will be the rescuers -- reinforces the power of the abductor.
I just don't think that children at age 11 realize they have an amount of control over their own destiny... they still rely on the adult and parental community for their needs. Escaping is not the first thought and I believe that is why children are such easy prey for pediphiles.