My pet theory is that there are financial incentives to make bad text books. Text books are usually written by university professors, often the professors from

My pet theory is that there are financial incentives to make bad text books. Text books are usually written by university professors, often the professors from whom you are taking the class. There are absurdly many entry-level textbooks for a subject whose beginning parts probably haven't changed in over 100 years. They do this at the behest of the university, which will be capturing their royalties under an IP clause in their employment contract. The university intends to sell this book for upwards of $200 to a captured audience of teenagers who don't yet have the life experience to know they can opt out of putting up with bullshit. If the university doesn't have a constant churn of new editions, then the books will very quickly filter into the secondary market where they will be drastically discounted. So universities pressure professors to write textbooks quickly. And university professors aren't exactly the best-paid vocation. Invoke "good, fast, cheap: pick two" and you see it's "good" that is getting dropped on the floor.