Just because a writer writes beautiful prose, in no way means she can carry off a story structure strong enough to sustain 100,000 words. Fiction, especially in reference to novels, is a highly intricate composite of many layers—characterization, dialogue, perspective, pacing, conflict, voice, setting, symbolism, arcs, themes, plot, scenes & sequels, and on and on. The skill and training required to write fiction well can be mind-blowing.