FWIW, one does not accrue debt doing a PhD in something like Machine Learning.

Depending on the program, possibly. But a PhD is not required to learn nor work in machine learning.

The debt incurred in a wasted PhD is not monetary; it's lost time.

Almost every good place pays their CS PhD students enough to squeak by without getting into debt. I wish this was more widely known.

And companies like Google are pretty keen on academic credentials. They've assembled what must be one of the largest collections of PhDs in history.

> Almost every good place pays their CS PhD students enough to squeak by without getting into debt. I wish this was more widely known.

Right. The debt problems that people have after PhDs are more often due to their undergrad loans sitting around for 4-7 years while they were earning enough to subsist and not more.