Yes, for me this is a much greater factor than attention span.
Reading The Iliad over the next three weeks on holidays, oh nice!
Reading The Iliad over the next three weeks while having a lot of other assignments from different classes, fuuuck me...
The article points out that the problem exists in a literature class, where well, you're expected to be able to read a complete book in some week in order to analyze it. That's literally the course.