I myself graduated as one such commodity PhD student, and I don’t consider it as a derogatory term, mere reality. Contrast to regular jobs, the PhD nowadays is more like the arts where the top candidates disproportionately reap the benefits. If you’re not at a top tier university or a star advisor your academic prospects are middling from the beginning. Not saying you can’t make it happen, a lot of my friends do, but it’s a slog and the system is biased against you. In the end there’s limited money and you’re directly competing the stars I just talked about before. Some people are just monumentally better at everything so it’s just not fun competing with a very small pie at hand.

The farther you are away from the top schools, the less the faculty are likely to see you as a potential peer or someone who might inherit or carry on their legacy. Combined with control over funding this produces a dangerous power dynamic.