I think that this book is well meaning but not very informed. The book's major premise is that graduate education needs to be reformed, mainly because most PhDs don't get jobs. Most do not. I have a PhD in English, and I've managed to create a career for myself. Cassuto thinks that PhD programs should offer graduate students more options. Right now--and he is correct about this--the PhD--like the one I earned at the University of Minnesota, is designed to get you a job at a major research institution. And the reality is that there are very few of those jobs. And if your PhD isn't from an elite institution, you're not going to get one of them.
Cassuto seems to argue that--at least in the humanities--one can engage in public scholarship or maybe get a job at a museum. How many jobs at the history channel or major museums are there? Not many. Cassuto--a tenured professor himself who seems not to have worked outside of the academy--doesn't understand what the real non-tenure track possibilities are. I'm 3/4 of the way through the book and he hasn't mentioned what real jobs there are. One can--if one is a decent editor--get several kinds of jobs with a PhD. But he doesn't seem to know what they are. Here are several possibilities: university press editor, course designer, corporate trainer, freelance copy editor, textbook development editor, ghost writer. Good ghosts can get 3000-5000 a pop for month-long gigs. I know because I've done it. Senior developmental editors can make 65,000 to 85,000 a year. Sales reps at big textbook companies can make nearly 100,000.
I teach at a community college (and yes it's a tenure line job). I find it so interesting that he spent a great deal of time talking about the evolution of the dissertation. He knows that community colleges are one of the few areas in the academy that offer jobs. (And don't kid yourself: those are not easy to get, either.) But he doesn't seem to understand that during most CC interviews, you're not asked at all about your dissertation. So, the nature of the dissertation doesn't matter at all. You're not going to be asked about it.
He talked about digital teaching, but he doesn't seem to understand that one of the hottest jobs out there is a corporate course designer. They can make a lot. But he hasn't even used the term course designer once. He also doesn't talk about the piles of educational content companies that employ PhDs. While Cassuto's book is interesting, it's not very savvy about possibilities for people who actually have to earn a living.