ebeth,
I think that is true. The older kids are being more tolerant etc. but it would be hard to find a truly mutual friendship with such an age disparity. I have been looking into Sudbury Schools which are "unschool" schools and it seems that the ages mix at times of shared interest but then age peers come together for other reasons. Of course the whole academic atmosphere is different. I have to say though that in observing my own and other children I do see the most engaged learning - and real understanding - coming when the kids are doing something they are really excited about and they are leading the activity, even if it is a video game.
In essence, I am beginning to challenge the entire education system and right when I finished my Master's degree in elementary ed.!