A better question is why do college students need buy new text books every year? What so drastically changes the fundamentals of a field of study that last year's text book must be completely replaced? No simply flyer with updates, no corrections from the professor, nope, most of the time they just reword a few paragraphs, move the chapters around a bit and print a new edition.
It's a total scam. And don't think it's going to change when things go digital. The only change will be no used book sales. You'll have just as many yearly editions, but you won't be able to turn your book in at the end of your class for a partial refund.
Oh and reading on any iOS device is terrible and just as much an eyestrain as reading on any LCD display. The Kindle has a great paper like screen, but it's far too small for a text book. If I was still in college I'd stick with regular paper books, my Android, and my gaming PC.
