I don't think people ever will. For the most part, I think people feel insignificant and they need something, such as a deity, to feel like they are important in one way or another. Or, for things that people do not understand or are unable to comprehend. When you look at the size and power of the Roman Catholic Church and the Vatican, with the enormous following that follows them (and the same can be for Mecca and the Muslim world), you would need some sort of event that completely disproves religious theory. Hell, even if that happened, I still doubt that people would stop needing a god.