Letters and books diverged a long time ago

Journals and monographs can look similar today, but they diverged a long time ago and they are fundamentally different shapes. A scientific article is more closely related to a dollar bill than it is a book.

Q: What else evolved from the letter? Levy has more on this

References

Yates, JoAnne. “From Press Book and Pigeonhole to Vertical Filing: Revolution in Storage and Access Systems for Correspondence.” The Journal of Business Communication (1973), vol. 19, no. 3, July 1982, pp. 5–26. https://doi.org/10.1177/002194368201900301.

As long as outgoing documents could only be reproduced in books, incoming and outgoing correspondence had to be stored separately. p. 14