The OP did not subvert anyone's revenue model.
Simply aggregating data is not violating any copyright laws nor protections. If so... most news sites would be in serious trouble. The OP was simply aggregating data into an easily accessible format for students.
The original creator retains copyright, but they can't prevent someone from linking to nor providing access to publicly accessibly information. If they truly want nobody to have access in this manor, they would have to block public access or restrict it in some form.
To use your book example. If the copyright holder of a new book posted the text in full on their website with no restrictions or payment necessary, and I reposted that text, provided attribution and a method to access the original content, then I would not be in violation of any law.