In this case, the wealth of A is not being compared with the wealth of the Queen of Sheba (which would be conceivable), but with the speaker's identity as the Queen of Sheba!
a is like B If a, then B Not B not a The force of denial in these sentences is ultimately based on similarly infelicitous noncompatibility between the implied attributes for comparison:  Let us further observe some unusual syntactic properties of the above sentences, which justify their being classified as "pseudo-comparative sentences".