You think chemistry textbook authors haven't read chemistry textbooks? Heck, you think they haven't read chemistry textbooks as references, while writing their own textbooks?
Again, it's not about reading. It's about either acquiring in a way that is infringing or producing output that is infringing. If you write a chapter with something like, "Ionic bonds are bonds that occur between two elements where one or more electrons transfer to a particular element," it's not copyright infringement for another author to discuss ionic bonds. It's copyright infringement to copy the material. It's copyright infringement to produce output that is the same or substantially similar.