As one data point, this only ever happened to me in my general courses -- a department would choose a book that several lecturers would use to teach hundreds of mostly disinterested students. In that context it makes a lot of sense; the decision maker isn't any single instructor, and there's a large pressure to instill a baseline level of knowledge into way too many people at once.

All of my courses with smaller class sizes were much more careful with their book selections; occasionally those books were still expensive (even used), but only if they were really the best tool for the job. Even with expensive books though, this kind of online subscription nonsense was never used.