That, or a downstream effect of people applying for jobs for which they do not quite meet the stated qualifications. Putting up "5 years experience" starts being a really good way to get ambitious people who have two or three years of experience, and so employers start using the job description to grab those applicants rather than actually-meeting-qualification.

On second thought, though, it's more likely due to H1B employment requiring an "attempt" to hire a qualified domestic employee. So once an employer has an H1B they want to hire, they have to put out a job description and fail to find an acceptable candidate meeting the listed qualifications.

This. My company creates fraudulent postings to hire H1Bs. The Americans we interview (1 per position to follow the law) are switching industries or otherwise have absolutely no experience.

Not "this" - @musgrove said he/she's rejected as "overqualified", so it's not a matter of being selected for interview despite lacking the experience