I don't buy this. I think people find it easier to make excuses about lacking some magical, unobtainable, abstract property like "the drive" than to actually put in the effort to improve themselves.
People over diagnose themselves so it seems more common than it is, but adhd is definitely real. Its not merely attention, its a set of traits like reduced working memory (and ability to utilize it) that manifest as difficulty in sustained attention / distraction. People who have it do a lot of other funny things than simply "get distracted easily", just ask the spouse of any person with add what _their_ coping strategies are and you'll get many humorous and perhaps unexpected stories.