They are as follows: large print and audio books (as they currently exist) are goners.
Large print books are going to fold relatively soon simply because e-readers offer something that physical books don't and can't: resizable font. If the characters on your Kindle or Sony Reader or iPad or what have you are too small to read, you can zoom in; no such luck with a paperback. And as more and more older folks begin to adopt electronic readers, the market for paper-and-ink large print books will continue to dwindle. Eventually, everyone who used to read large print books will have either converted over to e-books or will have died, leaving only those who grew up with electronic books as the norm.
How long will this process take? Beats me, but I know that large print book sales have been on the decline for a few years now and their profit margins are shrinking. I'd be surprised if large print books are still sold by major New York publishers five years from now.
Audio books are a different animal altogether: they're not being directly threatened by e-readers like the Kindle or the Nook, but their audience is dwindling as libraries (major customers in the audio market) are closing and downward pressure on pricing in the music industry means fewer and fewer people are willing to shell out $40 or even $50 for an unabridged audio book.
In my opinion, the future of the audio book lies in the paid download (à la the iTunes store model or a subscription model like Amazon's Audible). As we move away from physical media for everything from books (Kindle, iPad, Nook) to music and movies (iTunes, Audible, Netflix's "Watch Instantly"), I think the physical, compact disc audio book is going to go the way of the dodo. Unlike the print book market, which will actually continue to thrive for awhile in the YA and children's segments (chiefly because most parents can't or won't by a $200+ device for accident-prone children to read on), audio books haven't taken hold with that demographic because its constituents either haven't bought a CD in years or are unsure as to what CDs actually are.
What do you think, gentle readers? Am I right or am I right?