Whilst I do agree that rationality cannot be used to a perfect/infinite degree ergo the irrational parts of the ego must fill in the blanks to come to a quick and effective solution for particular problems, I believe that the irrational can be changed. The irrational is fixed and based on sets of rules; for me, I see nothing beyond it taking on would I would call a "deontological" approach.
I would extend my ideas as follows: one can never be a true egoist; one can only be an egoist to an extent which is limited by multiple factors, such as their willpower and their dependence on others to survive and (obtain what they need to) do what they wish. My experience tells me that all of these come down to the material circumstances in addition to levels and uses of technology; I have never seen evidence to the contrary. I support egoism because I do not see any valid logic which stands in the way of self-determination bar the interdependence of individuals in society, which itself is neither ahistorical (i.e. "fixed") nor impossible to achieve. Furthermore, we just need to look to the markets to see stimulated and fabricated wants to see how people appear free when their autonomy is limited.
