Well to see it from the perspective from the inside: we always have hundreds of openings, and I've seen openings for months and years without suitable candidates. Sometimes lots of bad applicants and sometimes no applicants at all.
That's for the niche openings. For regular graduate stuff new people start every single day.
It's hard to match up that with the fact that some people apparently aren't getting a single application progressed.
Yeah there are obviously unfortunate cases. But to put another unsourced number out there I would say 90% of open source maintainers are employed in some way or even directly to work on that thing.
The point of bringing it up is that those people would gladly give a pass on an interview to someone they already know contributes than some random graduate they don't know.