There is scope for putting "experience with x an advantage/bonus" instead of "must have x" if don't want to put off the vast majority of well-qualified applicants that are not likely to have x, but would like to be noticed by the people that do.
Especially if x isn't something very useful like experience with a framework you use, but something relatively trivial like knowledge of a CRUD app they periodically do a bit of data input into.
I try to review our job requirements every time they are posted (for a new hire or backfill) and move more things from "requirements" to "advantages". It is hard, though, because hope springs eternal.
Especially if x isn't something very useful like experience with a framework you use, but something relatively trivial like knowledge of a CRUD app they periodically do a bit of data input into.