Yes, it looks like ADHD symptom. It's called hyperfocus. People with ADHD often focus on something that is giving instant gratification (like learning new thing or trying to find clever solution for a problem). The other, probably simpler things are neglected. And no it's not just "caused by Internet and smartphones". I had this before I even got a computer. I was hyperfocusing on reading books (very shallow, just wanting to check what will happen next). TV was boring because it was too slow.