If you can’t get a job in your field with a graduate degree, why does anyone think that if you get a master’s, suddenly the jobs will appear?

Usually, you need a lot of less skilled workers, and as you go up in skill, the demand for the numbers of workers goes down. So getting something more advanced/specialized may actually shrink your pool of options.

Plus, people with entry jobs with graduate degrees are more likely to shift jobs because someone is offering a higher skill position with more pay, so entry jobs should become available more frequently. In contrast, highly specialised jobs requiring the masters degree and whatnot will have some quadragenarian holding it as a salaried/tenured employee.