I have a PhD in physics, where a much fewer percentage of people get tenure-track positions. I feel every grad student's pain here.
Mathematically the entire doctoral system is designed to turn out more PhDs than can be absorbed by academia. Seeing why is simple: If the number of academic positions is constant over time, then every tenured professor who advises PhD students can only expect on average one of his or her students to get a similar position. This is just the mathematics of population replacement. The problem of course is that many professors turn out dozens of PhD students, far above replacement.
The key for any PhD student -- regardless of field -- is to accept the fact that you will most likely spend the bulk of your career employed outside of academia. In engineering and many of the sciences this is understood, and people regularly go to tech companies and other places where the PhD profile is valuable. In humanities there aren't so many obvious places for PhDs to go HOWEVER this in my experience is more perception than reality. Marketing departments are full of English PhDs with very successful careers. The absolute key is to not define your skills too narrowly. If you bill yourself as, "I'm an expert in X, Y, or Z" you'll likely be disappointed, but if you can think of yourself as "I'm a good writer and problem-solver." you'll have a much better time of it.
Unfortunately when you're a student, the "system" has no incentive to prepare you for this likely reality. They think of their mission as turning out academics, and because of selection bias (every professor by definition succeeded in getting an academic position) it's a self-reinforcing belief. There is a huge risk of disillusionment and bitterness if you the student have unrealistic expectations. I maintain that if more degree-granting institutions looked at where their graduates end up, then with some simple adjustments they could make it a far more useful experience: For example shortening the time to PhD, providing greater opportunity to acquire marketable skills, and more interaction with program graduates.