> The only way you keep this person's wage down is increase supply - have lots of people with university degrees.
Again, the second part of this statement does not necessarily follow from the first. There are countless ways of tweak supply/demand of McJobs, such as low minimum wages resulting in a glut of retail locations , changing total hours non-degreed workers (read high-schoolers) can work, adjusting rules on temp workers, community college intakes, etc.
There a many variables, and increasing minimum wage impacting a subset of (mostly unskilled[0]) workers doesn't automatically mean an increase in income for skilled jobs.
0. I dislike the term, but it conveys my intended meaning. "Jobs that require no prior training" is unwieldy.