The entire point of the single paragraph linked by OP is waterfall was a misunderstanding, not a necessity of the era. If you want to see a valid method "back

The entire point of the single paragraph linked by OP is waterfall was a misunderstanding, not a necessity of the era. If you want to see a valid method "back in the 90s", see DSDM: https://en.wikipedia.org/wiki/Dynamic_systems_development_method https://en.wikipedia.org/wiki/Dynamic_systems_development_me... Meanwhile, the Royce paper that takes down the simplistic series of steps arranged in a waterfall, is a sort of formalization of an approach better visualized in late 80s as "the spiral model": https://en.wikipedia.org/wiki/Spiral_model https://en.wikipedia.org/wiki/Spiral_model The concept of both, well before the 90s, is you don't know what you don't know, so its faster and more successful and costs less to make, learn, and document from prototypes before you know, to establish what you're really making.