This is a common misunderstanding. My experience with ADD is that it's not just "doesn't pay attention to what someone else wants"; it's "I can't pay attention to what I want to pay attention to".
And yeah, I do think that ADD has some beneficial effects as well. Syphilis can sometimes attack the nervous system in ways that create permanent elevated mood. I don't think that makes syphilis "not a disease".
This characterizes Zimbardos more recent work on "The Demise of Guys" where you can learn an overview about it here[0]
The great issue is the vast amount of boys being misattribute with the condition, from predominately female teachers.
I was one of those boys, but I was one of the few lucky ones who's father is a doctor and never had me prescribed medicine I didn't need. I ended up excelling in upper school.
I don't know about you, but I've never had any problem focusing on anything I found interesting; even in high school 12-hour coding marathons were easy for me. In one of Hallowell and Ratey's books they talk about how a better name for it would be "Attention Inconstancy Syndrome". But we have the name because in our industrial model of education teachers expect controllable students, and so see our difference as a deficit.
All humans have limited attention spans, and different people have different limits. The problem for me wasn't my difference per se, but the expectation that I conform to patterns of behaviors that work for others. Now that I'm an adult and can define my own life, I'm no longer a "problem", just different.
So kids with ADD can't concentrate for hours on, say video games or other interests?
It's not "I can't focus on anything" but "I often have problems focusing on things I _want_ and try to focus on".
http://www.drhallowell.com/blog/adhd-self-assessment-quiz-2/
Since video games are designed to capture attention at the expense of all other qualities, they're like a last refuge for people who want to have the experience of really getting into something, but don't have the focus control for something more substantial.