My SO started a PhD program two years ago. We had to move across the country for it. Since then their PI has moved to another university in another state, so we had to move again as well. The new university is in a city. Our rent is $1900. Their income is $29,000 / year. They work 40-60 hour weeks. And this is for a paid RA position. The work of these students is what the group lives off of. It's sustainable for the institution, but it's awful and needlessly burns out driven and capable contributors. That's a standard case in academia.

Also as an MS research DSP engineer: I work with PhDs who know far less and are far less productive than me. In some fields, for industry, it may really be just a piece of paper.