Full disclosure: I'm a college physics professor. You're making it sound like writing a good textbook (or notes to take the place of one) is somehow straightfo

Full disclosure: I'm a college physics professor. You're making it sound like writing a good textbook (or notes to take the place of one) is somehow straightforward or easy. Believe me, it is not. I've taught out of half a dozen intro physics textbooks and served as a peer reviewer for portions of another, and some of them were just plain cruddy. Sometimes that meant actual errors in the physics (I got that chapter rewritten), but more often it was just books with unhelpful explanations or pointlessly confusing homework problems or weirdly flawed assumptions about what students using the book already know. In the past couple of decades, there has been a lot of research on what actually makes a physics textbook work, and a number of good, innovative texts have emerged from that (some of which look quite different from the traditional approach, in one way or another). The textbook authors I've talked to (good ones!) have talked about the care they put into gradually ramping up the level of sophistication in the suggested homework problems over the course of a semester. They've thought in depth about the pros and cons of different orders of the traditional material, and about what topics deserve emphasis and which could be reduced or cut. They've tried to strike a balance between rigor and accessibility of the material. None of that is easy to get right! And despite quite a lot of looking, I've sadly not yet found a freely-available intro physics textbook that is even half as good as the modern, research-based texts that I know. So despite having had concerns about the price, I've asked my students to buy good textbooks that I believe can form the basis of quality learning (and that don't leave me ranting to friends and family at night about how once again I'm having to teach around some substandard bit of a textbook). I have not studied the literature of Physics Education Research enough to be able to reliably write with equal skill myself. (Happily, the textbook I'm using now is sold as six smaller volumes, so at least the students aren't paying for content they won't use.) I'm not at all clear on which part of all that is "valuing kickbacks over what's best for my students". But I can tell you that I agonize over the choice, and I worry about cost, and I have still concluded that the best learning experience is going to come with the help of well-written textbooks by people who actually know what they're doing.