In one of his amusing autobiographical works, The eminent physicist Richard Feynman tells a tale of how he was on a team selecting high school textbooks. He talks about how incompetent the group of people on the "committee" was, and how the textbook company expected that sending fruit-baskets to the committee would make it a shoe-in.
As someone who gets tons of textbooks for perusal all the time, I can tell you that these things are not designed for students. Textbooks are designed to be 1) politically corrrect, 2) expensive, and 3) comprehensive. Interesting things do not get discussed, yet everything else does because the publishers want to make sure that no teacher has an excuse not to adopt it. Naturally if you need to use it, and the teacher gets a free copy, why should the company not charge as much as it can. TExt books are so expensive, that I applaud this teacher for tnot adopting them.
Personally I do use price and quality when evaluating texts for my classes. Fortunately I am lucky in that I never need to go through a process of approval before I get to select a textbook. I feel bad for the high school teacher who does. I feel worse for the students.