I was always under the impression that Donald Knuth “invented” notebooks in 1984¹. Maybe Mathematica was the first to implement it, but that’s not the impression you get from the article.
AFAICT, literate programming does not imply interactive workflow. Also, Mathematica notebooks are extremely flexible thanks to its lisp-like language, and it's not really about writing docs and code. You can draw diagrams, format texts and paragraphs, and embed dynamic/interactive elements. It's indeed the first and the foremost in its direction.