AFAIK, waterfall was always a straw man meant to knock down. Nobody sane ever did a pure waterfall model. The model came from
http://www-scf.usc.edu/~csci201/lectures/Lecture11/royce1970... and describes it as risky in that very paper. Notice diagram 2 (the waterfall), 3 (the dream) and 4(the reality).
We had expensive agile consultants coming in a bit after 2000. They were telling us the current official process, RUP, was waterfall, and we were completely misguided. Of course, this was a typical management-saves-face move: Devs were asking for using RUP as described (i.e. more iterative), even if managers expressly forbade the use of agile processes up to that point. RUP as intended was basically doing 2 to 4 week iterations, each a mini-waterfall (thou shall not call them sprints).
Somehow, expensive consultants delivered an agile more waterfall than RUP.
The actual value from RUP was a clear description of who does what, who requires what, and how do we call each part of the process. The Agile consultants saw no value in this, and gave us service based service service services implemented by services. We had standups reused as meetings to find out if service was meant as ITIL/SOAP/process/micro/business/something nobody ever heard of. This distinction was important so we could fill in all the important agile documents, which were not meant to be read by anyone, but filling them in was the only way us lowly peasants would not stray from the true golden agile path.
Oh well, if there is an ASCII code for the END-OF-RANT character, you can place it here: >