You are probably right, although I dont know how many of these textbooks are actually being refreshed that quick. Some of the ones we use go through a 4 to 5yrs cycle. And in this case I would not object heavy DRMing the content to give a better guarantee to the authors and publishers. At the end of the day, even a hard copy is easily xeroxed or scanned, having an electronic DRMed copy through iTunes, probably would not be that different.
My initial thoughts on the iPad did include a heavy student use, the ultimate media consumption for the classroom... Being able to have the copy of your book in the device, anotate on it, be tested on the device via some sort of classroom wifi etc... iBooks had a nice platform, how easy is to take notes on the book, highlight etc.. I thought was a nice start....
Along with that, in Feb this year, there was a good amount of publishers that wanted to jump on the iPad frenzy bandwagon, and the Big textbook publishers were present too...
Its my wishful thinking. I know... Soooo how do I email steve-o??? J/K