The way PhDs work in the US is that they dangle a carrot in front of you (research your own project, yay!) and then expect you to work 60-70 hours per week fueled only by a crappy stipend and your passion for your field. This works for some, but most develop terrible mental health issues from it even while working in a low cost-of-living region. It must be orders of magnitude worse for those who have to spend 70%+ of their pay in rent and basically don't have access to leisure activities or travel.

And it's not really a good deal, not at all. As I said Ph.D. students aren't really comparable to professional grad school as we are working full-time (+ classes +taiships +departamentalbullshit) from the very start of the degree. The school gets to sow all the benefits of having extremely qualified workers (grant money, publications, more prestige, T.A.s, etc.) while paying peanuts for it.

A PhD is more like an extremely poorly compensated job than a degree.