What I never understood is how remaining a child physically for years and years means you remain a child mentally. Doesn't years of experience add up over time? Wouldn't you grow in understanding and capability just from practice at taking care of your food needs? Just because you are a child doesn't mean you can't learn how to plant and fish, given time.
The brain is part of the body. If the children's physical development was arrested, their brain development would have been arrested also. Would you have been capable of learning how to scrounge and forage for food, let alone know how to plant crops, when you were 8, 9 or 10 years old? Maybe if you were born and raised on a farm, but the Onlies all seemed to be city kids.