As a college professor, I must disagree with both of your points.
I would love to use open textbooks and each summer I spend time looking them over, only to be disappointed in the quality of the text, the illustrations, the problem statements, the equations, the photographs, the grammar and the overall organization of the book. Writing an introductory physics text is hard. Most of the texts on the market have been around for twenty or more years and have been substantially revised by large groups of authors. If I could spend my "free-time" and write an intro physics book and publish it using copyleft, I would. I work hard to find textbooks that are inexpensive, I use Dover books or similar when I can if there is not something free. I tell my students about discount sites and that they are under no obligation to buy books from the bookstore. I try to keep the cost of books for each semester per class less than $80.
It's not just me, most of my colleagues would use free books if we could. Remember, college professors are all about freedom of thought and ideas. I can't imagine a professor that would want to lock down your ideas.
The only time I had a class where the professor wrote the textbook, he distributed it to us for free. The college as a whole sees very little money from the college bookstore. In most every case, college bookstores are no longer owned by the college, but run by a for-profit national business (usually Barnes and Nobles). The college gets rent and some money from marketing t-shirts and the like. The profit goes to the national bookstore and the publishers.