Josh, I hope that your experiment works out - in my undergrad studies I was able to get away without buying books for most of my classes for the last 2 years of college. The only time I needed to buy them was for classes where I needed to do work out of the books (such as math books, though I finished my math classes by that time).
As for the book idea, I think it is great, but I don't see how they can keep it that cheap and keep it constantly updated, and keep it with unlimited access to the original purchaser. IF they can keep a steady flow of customers, I can see two of those - perhaps constantly updated with permanent access, for example, but then I would think the price would have to be very high. Alternatively, I can see them keeping the price low, but using a subscription type of service - $20/year for access, $50/5 year access, etc. Personally I like the idea of $50/5 year access - people could still sell "the book" if desired (I can imagine a few classes that are considered worthless that I would have transferred my account if allowed). It is a sustainable price given constant updates, without the lifetime license issues that tend to kill constantly updated projects be they software or, in this case, books. Sure it is conceptually great for customers, but I have yet to find a lifetime license project that hasn't at some point changed the licensing to kill off the license option, stopped or significantly slowed update progress, or just killed the project outright. The only notable exception (so far) is xyplorer, and I am not convinced it won't change - just that it hasn't yet. I can only imagine this idea will suffer a similar fate if they try to accomplish everything claimed above.