I know kids who have gone to Christian school and still walk away from God. It’s really sad when even pastor’s kids do the same. It’s not that they haven’t heard the Word, but many times it’s just young people wanting to find out truth for themselves. They also often listen to their unbelieving friends. I think it’s a mixture of things. The world attracts them as well.
I have no doubt that what you say is true. I would like to know what you consider to be “walking away from God”, though.