I think that ADHD does exist, but I also think you have a somewhat valid point hidden in your sarcasm/trolling/whatever.
When I was in elementary school, I was consistently not paying attention, goofing off, and slacking on homework. When I did do my homework though, it was a breeze and always got good grades on homework. Same with tests, I always did well on tests, despite apparently never trying. Fortunately my teachers recognized that instead of having some sort of problem paying attention, they realized I was just bored by the subject material and not being challenged. They tried remedying the situation by putting me in some special classes for "gifted" kids. I think those were more geared towards keeping us bored kids occupied more than anything though. But they did have the benefit of letting us kids kind of guide our learning. We'd get to choose what we wanted to learn about, and the teachers would help us. They were basically teaching us to teach ourselves.
Anyway, fast forward to middle school, and high school, and it was a similar story. I wasn't as bored in school, since we had greater freedom in middle school, and especially in high school, to choose what classes we took. I still however, was at risk of failing a few required classes because I didn't put the time or effort into doing homework and such. I started putting in the bare minimum amount of work necessary, and it showed in my grades. My GPA was basically around 3 because I had a bunch of Cs and even a D here and there. Those were the classes I had no interest in, but had to take anyway. The classes I took that did interest me however, were all classes that I received As in. To give you an example, one of the classes I took that initially interested me was "Computer Programming". When I soon learned that it was just programming in BASIC, I started losing interest very quickly. My grades suffered because homework was the biggest factor in grading for that class. I aced the tests, but I still only pulled off a D in this class. Meanwhile, at home, I was teaching myself C++. Fortunately, in some of my classes though, the teachers recognized I was bored with the subject matter, and would even turn a blind eye to missing homework so long as I was doing well on tests, and not disrupting the classroom.
I have no doubt that if this happened to me today, I would be diagnosed as having ADHD or ADD or something, and be placed on medication.
Back to your "point", I think a big problem is the way we're teaching our kids. School is not a normal situation for kids on a basic level in my opinion. I mean think about it, we're taking kids and forcing them to sit at a desk for 6-7 hours a day. While they need to learn a lot of things taught in school, the way they're taught is all to often, quite frankly, boring. Try and get a kid to sit still at home for 6-7 hours doing something boring (even if it's watching TV shows they have no interest) and you'll probably see a lot of similar behavior. I think we need to work on how we're teaching our children. And this is one area where I think computers and technology can really have a huge benefit. We need to exploit technology to better serve our children's learning. Make learning fun. Give them access to resources beyond the specific subject matter that's being taught.
Okay, enough rambling.