In The Atlantic, the harrowing story of college professors discovering that their students have never read a complete book before. And it's an elite school story: it opens with an anecdote about Columbia, and features quotes from professors at Princeton and UVA. UChicago, apparently, has been spared.
The reason isn't that the students are incapable of reading a book's worth of information, but that they're used to short stories and excerpts, not complete works. Which raises the question of how important the specific skill of completing a book really is: if they could do it, technically, do they really need to?

There's been coevolution between the economics of packaging information and the increments in which people publish their ideas; for the last few centuries, a default way to sum up an important idea is to produce 200-700 pages about it. And since earlier generations were used to thinking in those terms (before digital documents and Xerox, it was much more logistically challenging to assign excerpts from a dozen books, so you'd probably read one).
So a lot of the intellectual tradition that schools are trying to pass on was first spread in book-sized chunks. It's hard to outcompete something that has a multi-century head start.