FWIW, people with ADHD can concentrate and focus. What you describe is typical of people diagnosed with ADHD. Here's a little snipet from an online site:
Children and adults with ADHD find it very hard to focus on boring mundane tasks, yet can focus exceptionally well on activities that interest them. In fact, when they are engaged in a task that is interesting to them, they focus so well that it is called hyperfocus.
Wifey B: I understand. And we are different than those with full ADHD. Now, opposite, not. We all are on some forms of sliding scales of so many things. We tend toward ADHD without being fully there. I've taught kids with ADHD and as with all kids, they were all slightly different, always dangerous and wrong to throw a blanket over any group. I've also seen hyperfocus to the exclusion of all else. As with anyone, the key is helping capitalize on skills and work around any issues.
Now, I loved school, all the way to doctorate. Hubby, loved school in his way, everything except the classes. He loved the music department and the choir and theater and sports and playing bridge in the Student Union. Even a subject that interests him, sitting down in a classroom for it for over an hour is horrible. Had online college existed when he went, I'm sure he would have preferred that route. I think he learned all my subjects I took from just laying in bed with me while I studied and helping me study for tests.