[syncsynchalt]

Agreed. The concept of "waterfall model" was given form by Winston Royce as a strawman for an argument he was making in an article, and it's disingenuous to say that it was ever a promoted model on its own merits.

I prefer to think of it as the consequence of software development being tacked onto most other existing processes, without regards for the practical needs of software development.

[ternaryoperator]

You're talking about the original waterfall model. But waterfall as a way of developing software in phases that tended to be long and were not amenable to changing requirements was in fact practiced in most enterprises for many years. And, while not the most efficient process, it certainly did deliver good, working software. Just not efficiently. Phone switches, manned space flight, most businesses all ran on software developed this way.