[bryanrasmussen]

I'm thinking maybe it is no longer as common an expression as I thought, given the people who've mistaken it here.

[spuz]

I think it didn't help that they used both meanings of the word "frustrated" in the same sentence. By adding "perhaps my frustration is unwarranted", it puts emphasis on the fact they are frustrated, not that they failed to become an academic. It leads the reader to believe they are in fact still an active academic.

I was only dimly aware of the second meaning of the word so I'm not sure how you would interpret it if you had a good understanding of the multiple interpretations.