It's not always the kid's fault. Several factors come into play. Sometimes its the parents who think the world is full of danger and everything out there can hurt their kids (blame internet and sensationalist media) so they overprotect them and keep them sheltered. Another reason is influence from slightly older kids who are lazy; worse is that parents don't do anything about it as long as they love them.
Kids are easily impressionable. Just show them how it's like to live, and they'll follow.