I just read through this article, but I think you are confusing ADHD with "hyperactivity" a trait common in ADHD, not so much in ADD...
Unfortunately this is a common misconception, and ADHD comes with many other less desirable features and the severity is different case to case...
ADHD is not some trend it's a real disorder, so just think about that when you are writing, many people have a very arrogant attitude against people suffering from ADHD, please don't be one of those people, (people who are suffering from ADHD might take offense).
That being said you have a point, that a few centuries back ADHD was not such a problem, you could be an hour late to work, there was plenty of work, simpler times, I also think many people with ADHD in those times became criminals and outcasts even famous pirates, there is also a much higher chance for people with ADHD to die in accidents because of lack of impulse control/motor skills/patience...
/FF