Ayn Rand did well in establishing an objective metaphysics for her philosophy, but then made the grave error in attempting to label the rest of her philosophy as therefore also objective, which it is not. The problem hinges on her theory of mind. The advances made within the cognitive sciences over the years are at odds with Ayn Rand’s ideas of human consciousness.
Namely, Rand rejected the Kantian dichotomy between form and object, or map and territory, which we now know to be true. The human mind thus far appears to abide by the innate limitations described by Universal Computation, and given it’s finite structure it is only able to approximate a subset of all of objective reality in producing a mental model. Human ideas, arising from a complex interplay between underlying physical laws manifested in the material brain–embedded within and occupying a finite subset of our Universe–are subjective in the sense that they are quite obviously not a direct isomorphism to the totality of reality. Any human thought process can never be proven to be a consistent description of any greater underlying process governing a part of or all of reality, by Gödel’s incompleteness theorems.
Rand believed that because we exist within an objective reality, her thoughts must therefore also be objective, when in truth they were merely subjective approximations. She neglected the fact that we are embedded inside of reality, emergent from its underlying processes. Thus the individual must be considered in relationship to the whole in establishing a theory of mind that is conceptually more accurate.
The rest of her philosophy concerning economics, politics, and aesthetics thus collapses. By what authority, if her thoughts are not objective, does she claim to know what will be best or good for the freedoms of the individual of all of humanity today and into the future? And is that goal necessarily a good one? In order to answer that, one must be capable of fully simulating all possible paths our Universe can take from the present and selecting the best one, using some definition of “good.” It’s not possible.