I'm going to agree that I think that the big win will be for the company who makes people believe that they're getting a real deal, something for free. I doubt it matters if they are getting some content for free (say, 10 books) or if they pay full price but get a discount on the actual device. But people like a bargain, even if it's only an illusion.
I'm not sure the idea of renting a limited number of books is quite as appealing, since I think in most cases, it defeats one of the real selling points of a reader - the sheer number of books you can store at any one time. But maybe it's just not preaching to me.
Finally - the how will we get the kids interested is my favorite question. It's been well over 20 years since I had to "invent" something for a class project, about the one thing you wished existed. It feels surreal that I'm currently living in the future I dreamed of when I was a kid - because ereaders, with their ability to store so many books at the push of a button - was exactly what I wrote up.
It's kind of nice to be living my own dream
Next up, flying cars.