There is pathos in that line—for those authors probably wondered at the same question themselves—and still do.
More than a century of me-too books have followed How To Write Fiction; by 1901, one already includes a chapter asking "Is The Subject-Matter of Novels Exhausted?" But what of the man who began it all? Though Cody went on to hawk correspondence courses, when the "well known novelist" published his first actual novel in 1896—the Horatio Algeresque tale In the Heart of the Hills—creative writing's first guru met with a twist worthy of fiction itself.
His novel tanked—and he never wrote one again.