I teach in a university mathematics department. I don't doubt that stories like this are real, but very few of my colleagues collude with, or indeed have much patience with, the publishing industry.
Indeed, the opposite is common. Walter Rudin is the author of several well-known books on mathematical analysis. The publisher, McGraw-Hill, jacked up the price of his books to stratospheric levels, and Rudin fought back -- which wasted him a lot of time, and (I believe) cost him a substantial amount of money. All so that students wouldn't be gouged when buying a copy of his book.
In the end, Rudin eventually lost. $95.56 for a very skinny (and quite popular) book on Amazon right now.
Moral: As content providers we don't need to figure out better ways to work with the publishing industry. We need to figure out better ways to work without them.
My graduate university kept a good number of copies of required texts in the library that could be lent out for the length of the course. Reserved copies (i.e., can't be taken out of the reserved area) were available as well. No student had to buy any books unless they wanted to.
I know a couple of people in textbook sales. Their job sucks, and the way they describe it is that there are two type of professors: those that won't talk to them, and those that try to maximize personal gain from the sales process.
The professors they deal with know the game, and just string them along with soft promises and keep asking for more nights on the expense account. The day to day job in textbook sales is just bribing professors with expense accounts.