Every single writer can't be Charles Dickens, James Joyce or Jane Austen.
Most authors only end up with one hit book, and the rest are duds, or just don't get the same pick up (or they only wrote one book to begin with, a la Harper Lee with "To Kill a Mockingbird").
But that's really nothing to be sad over. When you write something as enduring as "Gone With the Wind" or "Paradise Lost" you're still certain to never be forgotten.
(For the record, by "one hit wonder," we mean books that were actually HITS. They don't just have to be good. They have to be popular. Therefore, some of these authors probably wrote other good books, but they just didn't reach popularity).