Special Topic: Popular vs. Classic Books

Ok, so it’s the quintessential question, isn’t it? And probably will never be answered completely satisfactorily. But I feel it’s worth addressing considering some of the books I’ve been reading lately.
The obvious truth is: some books last, some don’t. What some people don’t want to admit is that whether or not a book lasts is not left completely up to luck and fate. Every year, hundreds of books appear on the shelves of our bookstores, fill the warehouses of online stores, make their way to libraries and homes. While they may be enjoyed by many individuals, the great majority of them won’t be in the bookstores or warehouses next year. In ten years, they’ll be in the library book sale stacks, because of the simple fact that no one is reading them anymore.
Does this mean the books are bad? Not necessarily, and in many cases, just plain no. Often these fly-by-night books address topics and issues which are very relevant to today’s readers. In the case of Young Adult and Children’s books, these books can be very important in helping readers deal with the issues they face every day.
However, while these books may not actually be bad, it has to be acknowledged that other books are simply better. As Aristotle wrote in his Poetics, “Clearly, then…the soul of tragedy is the plot [Aristotle was kinda obsessed with tragedy, but he is also talking about literary works in general here], and second in importance is character,” and, “the larger the plot is, while still remaining perspicuous [look it up], the more beautiful it is in virtue of its magnitude,” and, “poetry tends [Aristotle used the term poetry to indicate fiction, as opposed to history]…to express the universal.” (And don’t complain about me using Aristotle: it’s lasted over two millennia—that makes it classic classic.)
What I derive from Aristotle is that for a work to be really beautiful, or great, it has to: 1) express a universal truth—universal meaning it is relevant to readers in any time period, not just the present; 2) focus on both plot and character and not just one or the other—but plot is more important, because characters are…well…everywhere, but a plot makes it drama; and 3) contain a plot of a certain magnitude, complexity, and importance.
It’s easy to find books that meet these criteria, both in “classic” and “modern” literature. Take The Lord of the Rings. Or A Wrinkle in Time. The Giver. Johnny Tremain. The Graveyard Book. Black Beauty. Or even Harry Potter, though language-aficionados will complain about that one. Some of those books are decades old, some are new, some are still on the bestseller list. What they have in common is a dynamic plot, real and unique characters, and a universal truth that is expressed through them. There were hundreds of popular books from the decades of LOTR and Johnny Tremain that almost everyone has forgotten (trust me—I’ve read the old Horn Books). You probably can’t name 50 books from the years Harry Potter came out, unless you have a really good memory. You may not even be able to name two dozen from last year.
But you’ll remember the great ones. And so will your children…and their children…and probably their children.
Any thoughts? I'd love to hear your opinions on which modern books will still be around in 50 or 100 years!