I agree with your latter two points, but I must take issue with your first point about mental health. I've posted some links below for your further reading which can explain the stressors better than I can, but graduate school is a breeding ground for mental health problems -- you have constant pressure to always be working (often up to 80-100 hours a week), constantly comparing yourself intellectually to other graduate students, and dealing with the overbearing reminder that you need to take a candidacy exam and defend your thesis. As a poster above said, 30% is absolutely not normal for society as a whole. Most articles point out the dearth of students who seek help, which I don't think is uncommon, but what is uncommon is the additional stressors.

I don't know if you've been through a PhD program, but as someone who has, it's really difficult to explain the pressures and stress that you encounter during it to someone who hasn't.

https://www.sciencemag.org/careers/2014/02/paying-graduate-s... https://psychcentral.com/blog/highlighting-mental-health-in-...