Comment by kccqzy
My high school doesn't use entire textbooks; it uses either excerpts from a textbook or lecture notes produced by the teacher. This solves the 30lb backpack problem nicely: you realistically only bring the necessary notes or textbook required for the last few days of instruction. Anything that's earlier gets left behind at home because you won't need to refer to it often.
Interesting. This is actually a pretty nice middleground. If books were designed more like a binder of notebooks, perhaps by chapter, it would solve the weight issue while still allowing for all the things people love about paper books.