Waterfall Model이 많이 채택되었던 이유

In a typical quip, H.L. Mencken said, “For every complex problem, there is a solution that is simple, neat, and wrong.” In the history of science, it is the norm that simplistic but inferior ideas first hold the dominant position, even without supporting results. Medicine’s four humors and related astrological diagnosis and prescription dominated Europe for more than a millennium, for example.

Software development is a very young ﬁeld, and it is thus no surprise that the simpliﬁed single-pass and document-driven waterfall model of “requirements, design, implementation” held sway during the ﬁrst attempts to create the ideal development process. Other reasons for the waterfall idea’s early adoption or continued promotion include:

It’s simple to explain and recall. “Do the requirements, then design, and then implement.” IID is more complex to understand and describe. Even Winston Royce’s original twoiteration waterfall immediately devolved into a single sequential step as other adopters used it and writers described it.
It gives the illusion of an orderly, accountable, and measurable process, with simple document-driven milestones (such as “requirements complete”).
It was promoted in many software engineering, requirements engineering, and management texts, courses, and consulting organizations. It was labeled appropriate or ideal, seemingly unaware of this history or of the statistically signiﬁcant research evidence in favor of IID.