I'm glad you liked the article. I'm curious how you feel about the whole concept of tenure. Doesn't it create the very situation that is described in this article? People with lifetime job security appear to have created a guild in which no one but the proper sort can be admitted.
That is a good point. From my point of view, I do feel freer to speak out conservatively. (In fact, in the hall at school yesterday a student and I were admitting we were both conservative, even as another--liberal--prof walked by. We looked over our shoulders a bit, but weren't worried. I said "Different opinions, that's what it's all about anyway.")
Actually, at my school now they have post-tenure review. Thus professors can be in trouble if they haven't produced much since their last promotion.
But I don't think it weeds out many professors. I used to be against tenure, thinking one should prove oneself every year. But now I am relishing the freedom to speak out as a conservative, especially with the support of freepers. And the unions at my college are pretty strong and won't tolerate getting rid of tenure. They whined as it was with the post-tenure review.