I heard an argument that the fake jobs are actually to appease internal employees. "We know you are over-worked, but we are trying to get you some help. Look at these postings -too bad everyone who has applied thus far is a complete dud."
I've heard in the sales world, the way to hire two sales people is to hire three, then fire the bottom performer after a month or a quarter.
Effectively a/b testing job adds?
Or trying to get a range of candidates so they can find a good fit?
Let's say you have, like, 10 jobs to do but you're only going to hire two people (either loading them up with more work, or internally reshuffling responsibilities, probably a bit of both).
So you advertise for every role in your ideal team, then get the two candidates who plug the most holes, or look like the best fit.
I feel dirty suggesting it, but it probably happens.