Evolution is blind.
Not to mention, not all traits that survive evolution are positive.
I can’t be anything but thrilled that society has given me a tool that gives me some control of my concentration.
Some people manage to make lifestyle changes and/or dietary changes and/or ditch people who were part of the problem and see substantial improvements in how they function and in quality of life. They try to spread the good news and people feel like they are being told they don't have a real problem or something and both sides get mad.
I used to see this a lot on parenting lists. People would suggest homeschooling because it had made their lives so much better. People who didn't want to consider homeschooling would feel judged rather than feeling like they were being given options and hope.
Cue everyone getting hot under the collar.
There is the person I am and the person I have to pretend to be.
There is doubt that a set of behaviors which is so prevalent in the population is just an accident and a disease. Evolutionary pressures exist to optimize gene expression ratios in a population. Put differently, when a certain gene becomes rare in a population individuals with that gene have a significant advantage in life and reproduce more – when the same gene becomes over prevalent individuals with that gene have a significant disadvantage and reproduce less. There are traits which have pressure to be a certain proportion of a population.
ADHD or whatever else you may call it could very well be that. Ancient societies which had a small proportion of a certain kind of person thrived because their different behavior made them successful. It doesn't have to be a disease to not fit in to a certain society.