One reason I've observed is that the quality of printed text isn't necessarily that good. I can't not let go of a good book, I'm only bounded by the time of day

One reason I've observed is that the quality of printed text isn't necessarily that good. I can't not let go of a good book, I'm only bounded by the time of day and night: if I weren't, I'd read it on one sitting. Or an interesting textbook that I can't wait to get back to even if it's slow to read because it's just so interesting. But there are lots of books that just aren't that good in comparison to really interesting articles on the internet. There are a even a lot more articles, so the reader must develop the skill of skimming quickly and deciding early whether there's any meat in it. But good articles are really good and they're easy to find. Books that aren't bad and books that are just all right but not really, truly good can't simply compete: earlier they could because there was no alternative. But now there is. Nothing can beat a good book but there's so many other things to read that are incredibly good too, so the partitioning of our reading time will simply change.