My opinion on the matter is that every employer has unique expectations that they pretend are industry standard and obvious. I'll relate this to your statement by saying, they don't know how to try because interviews as a process are like crossing a field of landmines.

Too much academic work or management responsibility, they call you overqualified. To little: they say you aren't trying.

Enthusiastic for a low end job: we shouldn't hire them because their expectations are too high. To low of energy: they aren't the right fit.

This goes on and on and on as hirers act like their individual set of criteria bias are obvious -- likely because the interviewer themselves has limited experience.

Most people do best when they are told what to do in blind situations. Help them out with a few tips on what to expect and I'm guess you'll find much better applicant quality.