At least in my field, it would definitely be more of a “lured” scenario. Industry is much more lucrative than academia in the overwhelming majority of cases, and the work-life balance implications can’t be overstated, either.
I (so far) stick with my academic job because I like being able to work on anything I can convince someone to fund and I like having close contact with students (though they certainly try my patience at times).
I think there are a couple key points here. Usage of adjuncts is on the rise, but many universities, realizing this is not sustainable, are exploring “career-track” teaching professors as an alternative. My university is doing this, for example, so that a faculty member who really just wants to teach has more job stability and a more competitive rate of pay.
I think it’s also important to note that PhDs don’t have to get academic jobs in some fields (STEM fields in particular) but in others, there aren’t a whole lot of jobs that require a PhD outside of academia. In other words, I can see how the lack of tenure-track jobs could really destroy the mental health of humanties PhDs, but I’d be surprised if it had much effect on STEM PhDs considering most of them are targeting industry anyway.
Based on my experience, I think there are more fundamental forces at work here. PhD students are in an environment where an outsize weight is placed on one’s intellectual abilities and where every one of their peers are high-achievers as well. There is likely also a fair bit of self-selection of students who internally place a high value on their own intellectual and academic accomplishments. Inevitably, when these students have to confront failure, many times for the first time, it can be incredibly jarring.
This happened to me when studying for the quals in my program where, for the first time, I had to seriously confront the very real possibility that I just wasn’t up to the task and that failing this test would mean that I had to leave the program and abandon my career goals. In the end, it turned out I was far more worried about it than I needed to be, as I passed the quals just fine and could have certainly gone to get a different job in industry paying a perfectly respectable salary. Just the act of confronting those feelings and anxieties, though, led me to seek a therapist and to take some medicine for about a year.
Another factor in more modern times is, I think, social media. I know it was sometimes hard for me to see friends of mine on Facebook who I knew worked a fraction of how hard I did going on fancy vacations and buying homes and having a family and all sorts of these big life milestones that I had to put on hold. In the end, it was worth it and I am very happy with how my life has gone, but at the time, it’s a nontrivial thing to deal with.