I thought I'd share an Inside Higher Ed essay by Nate Kreuter called You aren't the exception. It's an essay on why graduate students are prone to ignore warnings about the job market and decide to pursue academic careers anyway.
Nate argues that as intelligent, driven and competent undergraduates we learned to ignore the warnings of our professors. We assumed wrongly that the words of caution didn't apply to us (because we were so damned good!). Of course, in reality, the statistical rules did apply--we were simply members of the statistical group that would not be adversely impacted. To put it delicately, we were arrogant little jerks.
So, this is the attitude that we took with us to graduate school. Perhaps, we can say that graduate school is an important point of divergence for the smart, ambitious and gifted. The arrogant ones go on to get PhDs; and the well-grounded ones, realizing that the bell curve that applied as undergraduates is now moot and that the odds really do stink, do something else.
When the professors say that 40% will go on to complete their doctoral training (and far fewer will become professors), they mean 40% of a much smaller and more select group! The well-grounded will go to (and pay for) professional school, stop at (and pay for) a Master's, or take some other less esteemed path that they realize has better odds leading to career success.
So, who are the ones who actually make it to the professoriate? (I mean, professors are amongst the most self-important people on earth, right?) Are they truly the luckiest of the arrogant ones?? I doubt it. My guess is, they realize the odds, decide they want to be a professor anyway, and are determined not to leave their careers up to chance. It is only then, after clearing the final hurdle, that they dare display their well-earned pomposity.