Prehistoric primitive humans likely had no need for delusion, they likely and almost undoubtedly just accepted the reality around them. That death is a natural part of life. They had no need of surplus and accepted what nature gave them as food, took nothing more and nothing less. This isnt to say they didnt have some worldview we might consider somewhat delusional, like animism. Its pretty much accepted that early primitive humans were animistic, the idea that all is imbued with spirit. This idea may seem absurd to us in the light of our current delusions and misinterpretation of reality, but is it that insane? Daoism and Zen Buddhism have these ideas, that we are all one consciousness experiencing itself subjectively. If you think about it, its quite logical compared to what many believe in today. But why are delusions rampant? Why is it that people do not seem to have a firm grasp of reality and in many cases knowingly reject reality for delusion?
I think civilization is so unnatural that humans seek out delusions in an attempt to explain their horrible reality created by civilization. That we are reduced to mere gears in a never ending and all consuming machine that labels itself "progress" and there seems to be no escape bears the question, why wouldnt humans create delusions to escape this newly created "civilized" reality? It seems human beings need delusion just to survive, just to avoid the sad reality that this forward progress is actually a progress towards species suicide, and potentially eco-suicide.
There is comfort in delusion. There is comfort because it gives us something to look forward to outside of this death machine. There is comfort because some of these delusions attempt to explain this reality and how it is either our fault or someone elses fault we are not able to live some lavish life. There is comfort in the idea that there is some master plan and someone pulling the strings of this said plan. If someone is in control, then there is a meaning for this mindless march of alleged progress. That delusional meaning gives us the ability to carry on, slaving for this civilization that reduces all of us to domesticated animals on a miserable slaughterhouse farm.
There is a need for many for these delusions, but for some we are beyond these delusions, we see them for what they are. We have no need of delusions and the dogmatism that accompanies them.