Your proof is found in the entire canon of software engineering prior to the late 1980s, when the concepts of &quot;prototyping&quot; and &quot;RAD&quot; became feasible.<p>When code was written by hand with pencil and paper, then translated to punch cards, &quot;prototyping&quot; was an exorbitant amount of work.  Moreover it added little value, as the first two entire generations of information systems were little more than electronic implementations of very-well-understood business processes.<p>I studied systems analysis &#x2F; engineering in the late 1980s.  At the time, the entire paradigm of software engineering was waterfall, with the exception that the idea of prototyping was just getting started as something you could do iteratively in the &quot;design &#x2F; build&quot; boundary.