Aren’t a lot of these grad students internationals? It’s immigration laws and culture that drive them into grad school, not the privilege of teaching undergrads.

Loads and loads of parents of international students push their kids into grad school because they want them to climb the ladder to the upper echelon. They don’t know how to accomplish this in the corporate world because that ladder is more like a maze of culture fit dead ends. Then it’s the immigration laws which make this path extremely risky (getting fired and losing your visa, then having to go home).

So the focus is on school, which they already know how to do well at. As long as you stay in academia, you can safely maintain a student visa. It’s your foot in the door. And then when you graduate with an advanced degree you’re much better positioned to get a long term visa leading to a green card.

I was one of those international students. It was 50/50 Americans/Internationals when I went to grad school 20 years ago, I am not sure if that has changed. Perhaps for some of the internationals you reasoning applied, though it did not to me, but for the Americans I think only an extreme love of research would keep you in grad school, when you can make 10x more money elsewhere, working fewer hours, under less pressure.