Pseudo-intellectual clickbait. I hate that I
know this will get bazillion upvotes here simply because of phrases like "carefully-considered cognitive model at their foundation".
> but the medium does have an implicit model
No, it does not. There is no such thing as universal cognitive model "for books". Every writer has his own. That's why there are so many different structures and styles of presentation. That's why some books are much easier to absorb than others.
Fuck, I don't write books (yet), just articles, and there are tons of different ways to handle this "mental modeling" even for short texts. It's not even always a good thing to pay too much attention to such models. Most writing is not propaganda where the only point is to imprint someone's brain with the desired information and opinions. It's a conversation. Accurately capturing your own mental model of the subject is usually far more valuable than overthinking the mental model of the reader - because you will have many different readers and (unless you're doing propaganda/marketing) you don't want to create something that appeals to a kind of faceless "average consumer".
The fact that modern books (even educational non-fiction) are a "lossy format" is usually by design, even if people don't think about it too much. It is not always the case and it was not always the case. For example, religious texts were designed to be "lossless". Epic poems were designed to be lossless as a verbal form and that continued to shape them when they were captured in writing. You can make a pretty good argument that deliberately lossy writing was a far more recent invention than writing in general.