Comment by barry-cotter

Depends on what they’re studying and where. If you’re a PhD student English Literature at Directional State University most of your compensation is consumption value, not the promise of a career[1] or pecuniary compensation.

[1] For the huge majority of PhD students in the Arts and Humanities there are virtually no jobs in their fields and it’s not that much better in the social or exact sciences, though there is at least some extra academic demand for their skills. There are very, very few fields outside academia where a doctorate is a necessary qualification or close to it and those are ~all a terrible investment if what you want is a remunerative career; things like biomedical research where you do a doctorate, then a postdoc and then get a job paying what an MBA from a top tier business school gets their first year out.