Zane's view is that books are good, important, and influential, but to take their influence to the extend Llosa does just marginalizes other ways society is affected, and doesn't really explain much. Literature, of course, confers many benefits.
Problem is, they are impossible to pinpoint.
It raises questions but offers few conclusions. It offers possibilities, not prescriptions. Love, anger, war and peace, community and individualism, each has its own bard. Because literature's target is not the mind, which is subject to logic and reason, but that roiling realm of subjectivity called the soul, its results can never be predicted.