Fantasy novels, or any other novel, relies on the author's ability to weave a plot and mesh characters.
They don't work as games. As soon as players get involved, the plot goes to hell and the player-characters change everything. Your average FRPG campaign is fun to play but would make a dreadfully dull novel. The Hobbit would probably have started with Bilbo pickpocketing the dwarfs or trying to murder them.
