As I thought about this model, I could not help but wonder how this increased ego-tism would manifest. Hypothetically, it decreases the emotional intelligence of the population. Such emotional intelligence is not necessary because the behavior generated by the memes substitutes for communal understanding. Another way of visualizing this is that religion could lead to an increased frequency of sociopaths, as sociopaths also do not want to go to hell.
Basically, religion operates as a social technology, anagalous to eye-glasses or anti-biotics. And just like how humans with poor vision or immune systems can survive in a world with glasses or anti-biotics, humans with poor social skills can survive in a world with religion. One might even expect parts of the human social brain being diverted to other tasks, such as finding a way to provide for the billions of people created by religion's general rules of thumb.