Starting from the assumption of a cosmology in which Boltzmann brains dominate over evolved ones, it is not immediately obvious to me that there is a real problem, since only Boltzmann brains indistinguishable from evolved brains will be posing the question in the first place.
In other words, the vast majority of Boltzmann brains will not be troubled by the paradox because their memories will not be consistent with a stable/large physical universe, and so they would never ask such a question in the first place.
So we must only consider the subset of Boltzmann brains whose experiences would be so consistent with a universe like ours that they would pose the question "why are we not Boltzmann brains?" And in such cases, even though we may be Boltzmann brains, our experiences would be indistinguishable from evolved brains.
Is this a criticism of the Boltzmann brain paradox that has been dispatched with, or is it a legitimate cause to be suspicious of whether it is really a paradox at all?