I highly doubt video games are causing the fall of religion. It's just common sense. Humans are evolving; becoming smarter with each generation. Smarter people tend not to believe in religion.
Evolution doesn't have anything to do with increased intelligence. It simply has to do with increasing the likelihood of surviving. So I don't think people are getting smarter with every generation. I don't think people today are that much smarter on average than, say, people from 3,000 years ago.
What I think you mean is that people are becoming more educated with each generation. Because of that education, they're generally less likely to try to invent an explanation for something they don't understand, but rather try to apply the knowledge they already know to it.