Its highly location based. On the coasts in SV and Manhattan Island, I'm sure McDonalds only hires high school dropouts and illegals, while anyone with a college degree has a real job. Elsewhere, it varies, and plenty of McJobs are staffed by people with degrees.

If the pie is continuously shrinking, and the supply of people with credentials (and related massive debt) is continuously expanding, this outcome seems fairly inevitable.

Most of the bartenders / waitresses I know have a degree in something. Maybe not a STEM field, but a degree of some sort. It is uncontroversial that there are unemployed people with degrees, so it should be no surprise there are massively underemployed degree holders.