Change takes time. I see atheism today as the Colorado River was 20 million years ago. If there would have been a human present to witness the flow of water, it would have been almost impossible to predict the mammoth canyon it would carve through the incredibly strong foundation beneath it.
Yet it is somewhat harsh to describe the non religious population in such a way. The number of people showing no faith is constantly growing and are even the majority in a handful of nations. Oppressive regimes and terror organisations place dams in the way of this irreligious river, not that it will hold for too long. I posted not too long ago that a PDF translation of The God Delusion in Arabic has been downloaded over 10 million times in the Muslim world, a large portion of this in Saudi Arabia. The Metaphorical dam is taking itself down, brick by brick under noses of those that built it.
So whenever anyone tells me otherwise, how religion is rising in previously non religious nations or is producing babies at a more rapid rate, I look at the picture of a river and how it can only be held back for so long.