(In this thread, I assume that religion is false or misunderstood. I don’t care to argue that point here.)
Communication likely developed continuously, increasing in complexity and expressive power with each generation. Communication began as it exists in out close animal relatives, as grunts, howls, etc. With each generation, the grunts were nuanced, and branching trees of nuance grew into language proper.
Throughout this process, there was perpetually a youth generation whose communicative power, and therefore communicative expectation, was greater than that of their parents’ generation. Each generation had a greater assumption of linguistic accuracy, because they were raised with that much more accurate a language; their own language ability exceeded that of their parents, and without this recognition they understood more from their parents words than their parents were able to say.
The result was that, with each generation, misunderstandings snuck in. From these grew myth, legend, and ultimately religion. What began as a truth that some elder struggled to express, ended as a belief born of over-interpretation of the elder’s words. Granted, with each generation, the inaccuracies that crept in were small. But over hundreds of thousands of generations, the result was significant, and secure in a cultural-linguistic context.
I think that we have since moved past this paradigm, and these inaccuracies do not continue to multiply. When language became complex enough to talk about it self, it lost the ignorance that was vital to the process. With deconstuction and the advent of the absurd, language changed to move beyond its own trappings, and in some sense it can trascend itself, and the ideas it carries can be understood beyond their linguistic expression. As a result, there has been a trend away from the misunderstandings that have been accumulated.
I propose that this explains the rise, and apparent modern fall, of religion. But if language is passed this point, why does religion persist decades past the proposed turning point? There are a number of factors: the first is religion’s prominence. Something as established as religion takes a long time to fade out. Furthermore, though language is developed enough to be used on itself, not all language users are so developed. This is not to say that all religious people are impaired, but there are significant statistical correllations between areligiosity and high-level education and other markers of cognitive development. Another factor is that the linguistic freedom that has enabled the abandonment of religion has also made it difficult for rival theories with more accurate linguistic foundations to gain ground, especially since, again, many are unable to cognize on the necessary level, and these theories often inherit the same flaws that religion exhibits, making them religious-type beliefs themselves, and thus making their rejection, in such cases, justified.