Article name is misleading, this is just another front where monopolistic influence and education meet.
Overall this is not surprising and has been happening for a long while in other areas, ever since near no risk loans for student education financing became the norm, prices have been marked up based on the expected projected revenue from these almost guaranteed loans.
Its been known for awhile that most of these engineering books have only nominal changes in problem sets, and material between editions and this predatory behavior has continued unabated for at least 20 years.
No one in a position to influence the outcome has been willing to make changes for the benefit of the students.
Much of the engineering principles taught in classes at this level have not changed for almost a hundred years so requiring a new edition of a book that is tied to a online subscription (as many are now) is simply predatory and monopolistic.
I've known some professors that have tenure that have bucked the trend and written their own books charging only the cost without copyright, but this is more the exception than the norm and engineering/science has a higher bar when it comes to due diligence with regard to materials.