Babi, at least 11 or 12 years ago I partly read a book by Nicholas Negroponte titled Being Digital or Going Digital, something like that. He was mainly talking about college texts but even then advocating online texts. One reason was that a major cost of textbooks is the cost of inventory and distribution. And of course, the ability to continally update.
About the Calilfornia decision. I think it offers the students a chance to explore beyond their text books -- new theories, differing viewpoints etc. Perhaps it would even help eliminate the biases that show up in textbooks -- such as the debate between evolution and creation.
It used to be said, maybe still is, that ALL textbooks were geared to what California and Texas wanted, because they bought the most texts. Remember Ma and Pa Grable, how they upset the textbook industry. At any rate, the teachers should be happy because the kids can no longer say, "I didn't have my book because . . . ."