Well it kind of is unique to text books. Rarely does an entrenched product get such price privilege, except perhaps Apple devices. Usually if the price becomes too high, the product becomes un-entrenched people switch to something else. University students are uniquely locked in in a way that few other consumers are.

> if the price becomes too high, the product becomes un-entrenched people switch to something else

Eventually, they do.

You don't know that this isn't going to happen here. In fact, I'd argue that it already started (but yes, it's a slow process).