Well, I mean, I read a lot of the Shannara books back in junior high as well as a literal FUCKTON of bad fiction because I read everything in junior high/high school that I could get my hands on, and that included a lot of crap. And I mean, a lot of authors that are prolific in their crap I read every single book of, if simply because its a lot of pages. Seriously, back then, the longer the series the better. Shannara series, Piers Anthony's XANTH series(which looking back is semi-dirty and wondering why they were in the school library), Animorphs , Everworld *shudder*. Jeez, especially in those last two the series weren't worth the paper they were printed on, but before I had video games I was reading a couple thousand pages a week.
I read the entire fiction section of my elementary school library, and I'm not kidding, I won a special award the teachers and librarians thought up for me when I finished that program, the one where you read books, take these computer tests and get "points" that you can use at the end of the year. By the end of sixth grade I had taken more of the tests than anyone in the district, and the only reason I didn't win by number of points the last year was because the only books left were like 1s and 2s (first and second grade level, also the number of points they give) and it just wasn't worth reading them anymore. I read The Hobbit and Lord of the Rings in the 3rd grade for the first time.
Now obviously I'm not attributing the popularity of Paolini's books to the idea that there's a lotta kids (as nerdy as) me around, but after you've finished your Harry Potter and your Artemis Fowl and Lord of the Rings(which is a hard trilogy for elementary kids to get into for the most part), you look around and see if there's anything else, or parents try to find new stuff to force on their kids, and lo and behold, there's this friendly looking book with a friendly looking dragon on the cover.