Simple: they don't need to.
They have enough folks deceived now to continue paying their tithes to keep the Leadership in the lifestyle to which they are now accustomed.
That is a bit more senical than I’m willing to be, at this point. But the more I learn of Mormonism and the more back-and-forth I have with Mormons, the more I’m leaning to a very high authority in the cult knowing they are duping the people but giving themselves absolution with some twisted rationalization. I mean, there is so MUCH error in Mormonism, how could someone with the full knowledge—which we assume the central thirteen top dogs have—of Mormonism NOT see the gross contradictions to the specious assertion that Mormonism is ‘restored christianity’? The apologists on these thread refuse to read the evidence, so they may have an excuse (though the scriptures caution, ‘they are without excuse’) for their ignorance, but the top dogs like Gordon B Hinckley, who played word games to avoid straight up full answers on the Snow couplet or the issue of blacks which would embarass the cult?