Oh I imagine there are arranged social activities. But the growing up with your peers is more than arranged activities. It's just being together with the same group of kids for 13 years. Now yes families do move so that doesn't always happen but there are so many other spontaneous things that kids do when they are together that help determine who they will be. From passing notes, to sitting next to the girl you have a crush on, to sneaking a smoke in the bathroom (well that likely doesn't happen anymore) to getting punched in the nose after study hall. Yes your children have friends in the neighborhood. But in school you are surrounded by dozens of other kids with all different personalities. The hallways of school is a great place to lean how to function later in life. Home schooled kids miss a lot of that I would imagine.