1. Let's face it -- nobody leaves the Church because they one day decide that General Moroni was a character created by Solomon Spalding. And nobody abandons their mission after a year, because some investigator convinces them that Sidney Rigdon lied about not knowing Joseph Smith prior to 1830.
These are not the reasons people abandon Mormonism. They are not the reason why my mentors, Vernal Holley and Ted Chandler (dedicated Spalding researchers) left the LDS Church. They are not the reason that I (host of SolomonSpalding.com) left Community of Christ.
Spalding-Rigdon is like a sherbet side-dish, following a steak dinner. It may taste good, after the main course, but it is not the reason you consumed the meal.
and:
2. And even more important -- non-Mormons don't care. The scholars, the historians, the evangelical anti-LDS fanatics, and the everyday man-in-the-street don't care WHY Joe Smith succeeded as a con man; they are content just to realize that he does not dominate their lives.
Accepting the Spalding-Rigdon authorship claims means that Joseph Smith must be demoted to a lower status in history. That demotion (to fellow co-conspirator) removes a very important LDS icon. People like to hang their hats on such an icon, and move on to talking about what really interests them. Re-arranging Mormon pre-history would be a messy job; too many books would have to be re-written; too many world views would have to be altered; too many interactions with institutional Mormonism would have to be "unplugged."
Many folks can vote for a Mitt Romney who just happens to be a member of a church ostensibly started by an old-time American genius -- a self-deluded polygamist, perhaps, but a religious Tom Edison, a theological Charles Lindbergh.
Who would vote for a Mitt Romney who was a participant in a conspiracy begun in the 1820s, to establish the political Kingdom of God on earth -- a conspiracy that began with a fake bible, designed to fool regular Christians into a theocratic cult, that has meticulously covered up its past?
Best to "leave sleeping dogs lie" undisturbed. Fawn Brodie provided an origin theory that everybody today can live with, Mormon and non-Mormon.
And, to paraphrase Martin Harris -- "What if it is a fraud? If you'll just leave us alone, we can make money off it!"
I left the church because of how I experienced it, because of how it messed me up and made me miserable, because of how on a subconscious level, I didn't believe any of it. All the facts and theories of it's origins came much later, and I wasn't surprised or shocked.