Power of Concentration Affected?

Over time, I’ve noticed an increase in the amount of intrusive thoughts I have while reading books that compel me to stop and take notes.

However, I don’t think the internet is primarily to blame for this, rather my literary/active reading training in college. I also think as I’ve gotten older I have more ideas in my head that want to connect with the ideas that the books present, and also I tend to read more dense material. I tend to read nonfiction theology books much slower than I used to read my YA fantasy novels, but I don’t think that has to do with a concentration failure, I just have more to concentrate on.