Anything Except The Fiction

Today I began work on a novel tentatively titled "Seven." Most of my life I've wanted to write fiction, but instead I seem to have written almost exclusively poetry, essays, literary criticism, scholarly theological polemics, sermons, etc. Almost anything except the fiction that I've wanted to write. Why do we so often do that--pour ourselves into everything except that one thing we most want? Is it a fear of failure? It could just as well be a fear of succeeding. I am hoping to have a draft by Christmas. We will see.