People with ADHD find forced motivation doesn't have the staying power that self directed interest does. Your entire comment is a textbook description of ADHD.
ADHD is as real as diabetes or arthritis. If that disturbs you, it says more about you than it does about ADHD.
I think folks are conveniently lying to themselves, and I'm not here to ruin anyone's party but I do get concerned in parenting circles when this kind of over-optimizing of normal laziness gets sold as childhood ADHD.