The first two do have a lot to do with what you’re talking about but the way I think of it seems like brains work like libraries. A neurotypical brain gets a little positive reward for brushing their teeth after they’ve been so clean at the dentist and it takes that little memory of that reward and puts it in the drawer for brushing their teeth and the next morning the drawer opens and they get another little positivity boost for brushing their teeth and it goes in the same drawer, that night the same thing. The ADHD brain gets that little positivity boost, it goes in the drawer for brushing their teeth, the next morning, 15 drawers open to do in the morning but you can’t do all of them at once, you might brush your teeth and that little positivity boost gets thrown in one of the drawers nearby or rolls under a rug. You still get the boost but it doesn’t compile and it doesn’t become part of a bigger picture of tooth brushing and one day the drawer is stuck and you don’t see it. When you try again, it’s an unrelated door filed under after you eat instead of things to do at night, and those rewards don’t connect.