Waterfall was a strawman, used in a paper as an ideally-bad project management strategy. The name was chosen on purpose to describe its fatal flaw.

Our industry being rather foolish, people read the paper and thought, 'hey, this sounds like a good idea!'

It's literally named waterfall in order to reference the idea that each step becomes immutable as it's being passed to the next step. This isn't some unfortunate consequence of an overstretched metaphor; it's literally the core concept.

It's not my fault that it appears you've been using the term wrong. Waterfall with feedback ceases to be waterfall.