The only problem with “The Book of Mormon” (you realize when thinking about it later) is that its theme is not quite true. Vague, uplifting, nondoctrinal religiosity doesn’t actually last. The religions that grow, succor and motivate people to perform heroic acts of service are usually theologically rigorous, arduous in practice and definite in their convictions about what is True and False.
That’s because people are not gods. No matter how special some individuals may think they are, they don’t have the ability to understand the world on their own, establish rules of good conduct on their own, impose the highest standards of conduct on their own, or avoid the temptations of laziness on their own.
The religions that thrive have exactly what “The Book of Mormon” ridicules: communal theologies, doctrines and codes of conduct rooted in claims of absolute truth.