For me, it's only partially a technical problem. If I need to really study something, I always print it out or buy the book. Honestly, I don't really understand why, but I'd guess that my comprehension and patience are at least double when reading a hardcopy.

Another advantage for me of physical books (etc) is that you have something like "tactile memory." What I mean by this is that very often, I can find where something was mentioned basically by how the book feels when its opened (e.g., how thick the pages are in each hand). A similar thing happens with shelves of books.

This is pretty hard to replicate with better tech.