Earlier quoted context omitted.
And who’s going to write and update that textbook? If your answer is “the professor teaching the course”, that’s cost-shifting and in many cases less efficient than having one textbook author write a textbook used in many places. If your further suggestion is that LLMs will generate college textbooks, that seems like a gross overestimate of their current capabilities.
It's the gatekeeping that's the problem. A royalty on a textbook for the actually author is very low, maybe like $10 on a $100 textbook? Replace the editors and layout designers with AI, the printing and binding with PDF, and the campus bookstore with Shopify or the like and make the same amount of money on $15 textbooks.
As an undergraduate, my first-year maths "course notes" were actually a textbook in all but name, produced by the Mathematics department and sold for a very modest cost, bypassing the publishers and the campus bookshop because the markups by both were outrageous
Even if you'd paid the authors $10 per copy it would have been a bargain.