I recently went on an analogue book binge, and discovered something I'd not previously noticed. Possibly for commercial reasons, books tend to frequently be much longer than they need to be, (coincidentally) they're often a minimum of 200-250 pages. Books that could easily have their content conveyed in 25 or 50 pages will be padded to 200. And not just literary trash (of which there's a lot) but books that are highly recommended reading.
Another big disadvantage of books is you receive exactly 1 perspective. Whereas if you actively research a domain with web access, you can cross reference and absorb a variety of contrasting (/conflicting) sources, and by smashing the ideas together enough, you can figure out which arguments are strongest.
I'd also argue the study mentioned in the article is unfair. Not understanding English from the early 1800's doesn't make you an idiot; a lot of the context and literally the words and language itself are very different to modern English. I can sometimes more easily understand written Greek, Spanish or French (I don't speak any of those languages) than old English.