. . . because civilization would truly collapse. Why do I say this? Because not only are young adults–you know, the ones who would have to carry the torch, as it were–largely illiterate (or at least massively subliterate and/or a-literate), but most of them don’t even know how to hold a writing implement like a pen or pencil.
Seriously. Watch a 20-something try to write anything with pen and paper. Almost every one I see nowadays has the most awkward, cramp-inducing grip imaginable. This, of course, results in nearly unreadable penmanship in many cases and is sure to induce the dreaded “writer’s cramp” in short order. Without the ability to comprehend the millions of volumes of written “dead tree” text (no matter how laboriously they may be able to decode those funny lil squiggles on the page) and thumb-text in “pseudo-L33T” on their ubiquitous dumb phones, the transmission of information is bound to die.
In short order, what was once civilization will be back to the Dark Ages where people don’t even know what used to be possible. Though it’d still be an order of magnitude more advanced than the typical Muslim society today, it’d be back to life as “nasty, brutish and short” in a generation.