Based on the information you provided, your son "might" have ADD. My son (ADhD) and I (undiagnosed) have similar "issues". Easily distracted, less focus on things we "have" to do, hyperfocused on things we "want" to do. Have we outgrown it? Yes, and no. My son, now an adult in his 30's, seems to have outgrown it. I feel like I taught myself how to "deal with it".
If I had to pick one thing that made a difference for both of us: exercise. Find something that will just flat out exhaust him. I had my son in TBall, Basketball, Soccer, and Scouting! If one sports season ended, I signed him up for something else. Children don't play like they used to. I walked to school, now parents drop the kids off at the front door (for valid reasons). When I was a kid, recess and art offered brain breaks. Now those things are being eliminated from curriculums. We need those things to be healthy.
Teachers: I found that my son's teachers wanted the entire class to sit at their desks, be quiet, and pay attention. That makes their jobs easier. And honestly, if your son is going in a different direction than the Teacher, he might just be bored with the material. If he can follow detailed diagrams -- maybe 1x1 is a little too easy. (Just an example, I don't know what he's studying.) Consider his homework assignments, is he having trouble with it or dismissing it because he knows it already? Can he read and comprehend what he's read, or is he struggling? If everything is easy, maybe he should skip a grade(?). If he's having difficulties, perhaps a little one-on-one time explaining the lesson.
I would determine if he is in the correct class level first. After you address that, increase his exercise for a few weeks. Let his Teachers know what you are trying. Make sure they know that you appreciate their input and that you want to know about any changes they notice while you try this route. They will be a lot more cooperative if they know you are taking them seriously.
If nothing seems to resolve the "issue", ask your Pediatrician about testing him for ADD. There is an upside and a downside to this. The upside is: the school HAS to help him with IEP plans and 504's (whatever modifications he needs). The downside: Personally, I think Teachers rush to get the kids medicated. It makes their jobs easier but I'm not convinced that it's always the best thing for the kids.
I wish I could offer the comfort of statistics for you, but I don't know of any. I hope that you will take comfort in knowing that most kids with your son's "issues" are absolutely brilliant in their own rights. I know, I'm one of them. ;) -el