Actually, it's not so nonsense. It's just stated inaccurately.
Dr. Keown at the Pamplin School of Business at Virginia Tech has been using his own book for years and years. If you are in the finance program at VT, you are going to take his class. Capacity for the two courses he is teaching this year equal to about 1100 students. He integrates an online passcode for the homework end of things and generally updates his book about every other year. The book costs the student $149 (no tax on textbook sales in Virginia). The book and the passcode are required and unlike other passcodes that can often be purchased separately, this one is only distributed with a new book. Now for the big bombshell that will certainly make everyone cream their pants: he also has been on the Board of Directors for the college bookstore (which, for full disclosure, is owned by itself and not by the University [cf: "axillary enterprise"]) for at least the last 8-10 years. That's only one example at one school; I'm sure there's others. He's not getting kickbacks, but he damn sure is getting royalties to the tune of close to 2000 students a year.
Just to throw this out there: the average retail markup on textbooks at the college level is 22% for new books and closer to 35% for used. Those of you who think the book you sold for $2 ends back up on the shelf for $80 are not really clear on the process: you're getting $2 because it's not being bought by the bookstore but rather a national used book dealer, and that's what the demand is worth. Sometimes that $2 does end up back on the retailer's shelf, but only because professors are really crappy about when they submit adoptions to the bookstore: if they wait too long, then the bookstore has to buy from the national dealer instead of buying directly from the student. Generally speaking, if the demand is there and the supply is not, the bookstore would always rather pay the student than the national dealer because if nothing else it breaks the ill will cycle. Now, those school-logo'd tee-shirts... that's where the real money is in college retail sales. That stuff commands a 55% and more margin. Then again, if you think that's outrageous then you don't know retail clothing practices well at all.