Another factor I’ve wondered in both myself and others: those who choose to be grad students often do so because of irrational unresolved issues or dissatisfactions with life. Grad work doesn’t help with these issues at all, only adds more problems or compounds them, and leaves you with a good amount of bitterness that you might not even understand.
Increased age or progress increases the chance that these unresolved issues are manifesting or compounding.
For me, I was looking for things in academia that just weren’t there, and I was too dumb to know what I was really looking for.
I don't know if there is any data on this (I would be really interested!), but anecdotally I would agree. I see high avoidant/anxious/ADHD traits in many colleagues and fellow researchers. In my field certainly way above average levels of the general population.
And I myself am a bit guilty of becoming so competitive and entering grad school partially because of unresolved issues.
Increased age or progress increases the chance that these unresolved issues are manifesting or compounding.
For me, I was looking for things in academia that just weren’t there, and I was too dumb to know what I was really looking for.