I don't believe this is a valid thought in this form, or maybe you failed to formalize your intuition enough to communicate it. You list a few specific failure modes, which I don't believe can cover enough of the theistic people to reduce the probability of a theistic person producing valid singularity thinking down to nothingness. Also, some of these failure modes overlap with related failure modes of non-theistic people, thus not figuring into the likelihood ratio as much as they would otherwise.