Someone else gets it.

Atheism doesn't spread from a successful ideological struggle for the allegiance of the human mind; atheism arises organically from the fact that humans have a weak attachment to religion, and they lose interest in it when they enjoy adequate socioeconomic conditions.

So says Nigel Barber in a piece, "Why Atheism Will Replace Religion," on The Huffington Post:

The reasons that churches lose ground in developed countries can be summarized in market terms. First, with better science, and with government safety nets, and smaller families, there is less fear and uncertainty in daily life and hence less of a market for religion. At the same time many alternative products are being offered, such as psychotropic medicines and electronic entertainment that have fewer strings attached.

I've wondered about the "alternative products" which compete with religion. Do they succeed because they display supernormal stimuli? Until recently I worked with a barely literate woman who has expressed no interest in religion that I know of, despite volunteering other things about her life; yet she had read all four of the Twilight novels and then had to tell me way more than I cared to know about them. By comparison, most people in developed societies don't find the gospels that compelling as discretionary reading; the Jesus story bores modern people, in other words.

Indeed, why do Americans, at least, display "rational ignorance" about religion, yet many of them go out of their way to learn useless things, like the people who study the made-up Klingon language, memorize sports statistics, write concordances of Tolkien's works, etc? A pharmacist who worked with my father back in the 1970's knew just about everything knowable about baseball cards, for example, which made him Tulsa's leading expert on the subject. Talk about putting a lot of effort into a trivial accomplishment.