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non-linear writing has existed since 1975 with 'Choose your own adventure books. Where the decisions you made would direct you to different sections of the book. I enjoyed reading them in the library as a child.
Steve Jackson took this a step further with his 'Fighting Fantasy' series. These simulated the feel of a role-playing game, which you could play on your own.
As a loner child with an active imagination I used to love these books. They were not books to be read. they were designed to be played. Flipping back and forth from page to page with decisions that could kill your charecter! This interactivity and engagement was my first experience of a non-linear narrative.
Excellent fiction can grip a reader - but it's passive. The reader is along for the ride with the story.
Pre internet the Zettelkasten was used for note taking and content generation. However it was rare and only used by a handful of people world wide. In large part due to the friction of analog technologies to build such a system wasn't worth it for most people.
The ease of non-linear writing have been unleashed by recent technology hypertext.