Let's face it: most writers quit. They may start with an idea for a novel, a memoir, or a non-fiction book, but (if the polls can be trusted) over 80 percent give up before they finish.
What makes them quit? Lack of discipline? Failure to commit to their project?
I suspect that the answer is simpler and sadder than we think: Most writers just don't get the kind of timely reader feedback they need. As a result, they succumb to excruciating, energy-sapping uncertainty—which can lead, in time, to abandoning their writing project.
Feedback from Oral Storytelling
Oral storytellers have an advantage when dealing with this kind of problem. How? They tell to live audiences and adjust to instantaneous listener feedback: facial expressions, laughter, body language, etc.
Such rapid feedback not only allows the teller to make rapid changes in a story, but it also reduces uncertainty.