Just to give perspective on how rapacious the textbook industry has become:

When I was in nursing school (graduated in May), even though I "purchased" the textbooks, it turned out what I purchased was only a license to access the textbook through their proprietary e-reader app for the semester. As soon as the semester was over, my access to the textbook disappeared.

This is the model that the textbook companies want. No more reselling used books to even recover a small portion of funds.

This is why piracy of textbooks is thriving.