I get a sense that the author seems to argue that most book authors are not conscious of the working memory of the reader. I don't think that is true. Many "good" non-fiction books I've read actually rely on space-repetitions throughout the text quite heavily. The author, to their credit, does note this for textbooks. Often concepts in long texts are referenced in a non-linear manner, either in expectation of ideas to come or in retrospect to draw parallels & new connections. Unfortunately, the onus here is on the reader to realize and extract the maximum juice out of this non-linear flow.
The key idea of this post is to shift this burden to the "medium" and not the reader. Books can't handle this responsibility in their current form. I certainly agree with this. Distill [1] is pioneering this from the perspective of medium-reader engagement. Unsurprisingly, Michael Nielsen, a collaborator of the author of the post, is a member of the steering committee at Distill. :-)
I love these new directions in dissemination of ideas!
[1]: https://distill.pub