The choice of textbook edition, new or old, and what is deemed required for a course sits with the Instructor.

An Instructor may have a valid reason for choosing to adopt a new edition if the content is significantly updated or they feel the electronic component of the book (an access code which can only be used once) is extremely important to the learning process.

If students organize to make Instructors aware of the benefits and their desire for use of older editions (where appropriate) and if Instructors commit to using one edition for a period of a few years the more used books become available at a significantly lower cost than the new editions.

Quiver is right. The Pearsons & Wileys of this world are never going to give away content for free or stop trying to push new editions out because their goal is to keep consumption and profits up.

However if students can work with the Instructors to come to an understanding that older editions are preferred and if a book is deemed required, Instructors support the use of the chosen course materials by utilizing them as much as possible throughout the course, more used books at lower price become available and the cost of that book is a bit more easy to swallow when you are really using and getting the benefit out of the content.