A common misconception about academic life is that once a professor has tenure, they can simply coast and have no incentive to do otherwise.
This might be true if salaries were guaranteed for 12 months. They rarely are. For example, the UW pays 2/3 of my salary. I raise the other 1/3 on grant funding, or I don't get paid.
So when I write a multiyear grant, I may have a year's salary riding on a proposal where to be funded I have to be ranked above 90% of other, similarly motivated faculty.
@ct_bergstrom Mostly agree with your statement on coasting, but disagree that tenured faculty face greater uncertainly than employees of private corporations.
There's almost no chance of losing a tenured faculty job, but of course layoffs and bankruptcies happen all of the time in the corporate world. Add in recessions and, for older employees in tech, rampant age discrimination during peak earning years and it's not uncommon to experience long periods of unemployment. I know, because it happened to me!
@twitskeptic Point taken!