Pure pulp will, I agree, largely leave the printed medium. Items like Twilight may I suspect stay around as they're 'a collectible series' in spite of perceived literary merit, almost as posters or similar do today.
I've compared the future of the book here before to the future of the horse in the early days of cars. They will retain a luxury and a prestige with enthusiasts for certain specific applications, but their previous general usage will likely vanish.
What will remain in print? Some may want classic texts like Don Knuth's TAOCP, though personally for that sort of thing I'd always rather have an eBook. I foresee primarily luxury 'coffee table' books - lavishly illustrated, beautifully made, designed to be objects of desire in themselves, independent of their content.
Otherwise, we're talking legacy content. I have a 1980 copy of a huge, library reference quality world atlas that can be pried out of my cold dead hands thank you, and a few other similar volumes, but pretty much everything else would frankly serve me better as an ePub file on a home server that could get synched to my various devices.
As an aside - I would LOVE a historic online mapping service. The ability to view a map moving through time, communities displacing, rivers changing course, harbours silting up, whole countries appearing and disappearing, simply by selecting an area and scrolling along a time axis, would destroy my ability to achieve anything productive for a very long time ;-)