WTF is up with kids is that there are far more ways to consume media than there used to be. Interestingly enough, the Harry Potter series caused a bump in literacy, but once the books were all done, the kids went back to doing other things. It's driven some interesting trends - Hunger Games doesn't happen without Harry Potter, but neither does Twilight - but the fact of the matter is, a book has to be worth it and most "children's books" are derivative of other media. A video game is going to be a more immersive experience than a book. It's also going to be a more profitable sale. What we're left with is an uphill push to get the books that aren't yet videogames into the hands of kids looking for adventure and escapism. Based on what I've been reading we simply aren't accounting for the massive shift in content from the written word to the interactive tale.