In a Business Insider piece I read that:
Michael Madowitz, an economist at the Center for American Progress, says he is "unusually unsympathetic to the evergreen skills gap critique."
"First the Econ 101 'pay more for more if you want more' cuts against this well in a period of little wage growth," Madowitz said. "Second, there's fascinating/depressing empirical research showing a 'skills gap' occurs because employers add and remove qualifications for the same job postings depending on the labor market, ensuring there is always a skills gap."
Unfortunately, the article has no further details on the latter research/issue to back up this statement that at least some of this "skill gap" is just employer advertisements vagaries, presumably regardless of what the job actually requires. And I'm curious if this is remotely quantifiable, i.e. how much of the "skills gap" in some sector (under study) turned out to be of this ad-based kind.