Textbooks being expensive has nothing to do with the textbook. The textbook as an actual object of learning is irrelevant; a textbook is just a fee added on to the cost of the class that happens to come with a physical pile of bound paper that may or may not be useful. It's unfortunately a rather regressive fee that also generates a lot of landfill waste.

There's little to be said about the way the economics of higher education have gone in the past few decades that's been positive for either students or educators, and this is just another symptom of it. As someone who's live in a college town for most of his life, it's rather depressing to watch the n-order effects.