The theory I am suggesting is that any global religion has existed for this long because it contains attributes beneficial to human survival ( benefits to human survival are not limited to the promotion of literacy; though I would bet that is a key attribute).

Are you familiar with meme theory? A seemingly stronger hypothesis is that global religion has existed for this long because it contains attributes beneficial to survival of global religion.

Edited to add: It is not clear to me that literacy is beneficial (on net) to human survival in an environment with little written knowledge available; there are certainly benefits to be had, but opportunity cost as well. If it is, in fact, directly beneficial, it is also not clear to me why people wouldn't adopt it in the absence of religion.