Inside Higher Ed has an article called “Moving Beyond Tenure” that you might enjoy:

Tenure creates a do-or-die moment 15 years into a career. What other profession has anything even vaguely like that? At least in law firms, if you don’t make partner, you have the option of putting out a shingle and starting your own practice. Most of us can’t afford to start our own colleges. After years of extended graduate training, some post-grad-school bouncing around, and more years of tenure-track teaching and writing, you are either set for life or summarily fired. No wonder people are edgy!