Maybe I wasn't clear enough? I didn't say atheism leads to a secure and prosperous society, I said a secure and prosperous society leads to atheism.a similar idea (ie ideal atheism) was prominent circa 18th/19th century.
Events of the 20th century give cause for recourse however .....
So, if you were to find yourself in a secure and prosperous society - more than likely it'd be an atheist one and if you were to find yourself in a very insecure and poor society - more than likely it's be a theistic one.
We can't USE atheism to form a secure and prosperous society. We should therefor USE THEISM to do so. Which means we just need to determine what kind of Theism we want to create. Should it have Aliens? Gods? Goddesses? All of these? Then, AFTER we reach a state of a secure and prosperous society it will naturally become atheist.
It's happening even as we speak. Iraq is becoming more theistic and the USA less so.