"They get weeded out at early stages for software engineering positions ("Have you ever used a version control system" is a Damoclean interview question)."
If by "Damoclean", you mean "capricious", then I agree, but it sounds more like an interview anti-pattern. That question doesn't tell you anything about the candidate's capability of understanding a version control system, which is a far more important property than their particular experience with one VCS or another.
This year alone, I've learned at least a half-dozen new tools and technologies that I'd never used in grad school. Yet here I am, using them to do productive work. Would you really not hire me because I'd never used a tool before?
I know this sounds unkind, but it is not a question of whether someone knows a particular tool, which I agree is not always essential. The overwhelming chances are that if a person has never used any version control system at all, they have not written software of any complexity and/or they have not written software in collaboration with others. The fact that they could, in fact, happen to be brilliant at both of those given a chance is an unknown quantity - and a pivotal part of hiring is to minimise the risk of someone not working out.
Of course there are always good answers to questions even when the skill is not there; personally, I have yet to get one on this question.
My advice to anyone who is a non-comp-sci grad (or lacks real software engineering experience for other reasons) that wants to turn into a programmer is to join an open source project and cut your teeth on that; not only is it going to give you an introduction to many things that count but it does so in a way that makes it very easy for a potential employer to verify them.
If by "Damoclean", you mean "capricious", then I agree, but it sounds more like an interview anti-pattern. That question doesn't tell you anything about the candidate's capability of understanding a version control system, which is a far more important property than their particular experience with one VCS or another.
This year alone, I've learned at least a half-dozen new tools and technologies that I'd never used in grad school. Yet here I am, using them to do productive work. Would you really not hire me because I'd never used a tool before?