You might have to discourage professors from requiring specific textbooks to achieve this. To me this seems like a mostly US-specific phenomenon, while textbook

You might have to discourage professors from requiring specific textbooks to achieve this. To me this seems like a mostly US-specific phenomenon, while textbooks were somewhat expensive here in Germany, not to the same degree as in the US. I think my most expensive book was 80 EUR, most were cheaper than that. And almost no textbooks were actually required in the courses, most of the time you were free to choose between several options, and using older editions was not an issue. If the courses require specific textbooks in specific editions, the students don't have a choice and have to accept excessive prices.