It may be difficult to follow my non-linear thinking here, but this is why the things that have really advanced atheism are not logical arguments. It's penicillin, knowledge about cholera, vaccines, and the like. Medicine makes people a little less dependent on the opium of religion than they were, say 100 years ago when death was a pretty common feature of the average person's life year after year. — Mongrel
Boy, I even wrote a paper on that! Not published, of course.
My point was the same: People needed, it seemed to them, an external force to protect them. Danger came in many ways: disease, but not just disease: crop failure, enemy attacks, fire, flood, even meteorite hits (ask the mainstream dinosaurs) and attack by wild animals. People froze to death in the winter, and starved to death during the whole year. Lords, landlords, had absolute power over the serfs.
Obviously their only recourse was superstition, to stave off the "evil". It has been seen (not by me) since prehistoric times, the invocation of protection via prayer, sacrifice, covenants.
The spread of atheism occurred at times when less and less superstitious dogma was deemed as needd for survival. There were sporadic atheists at all times in history, but the real blow to the Church came in the time of the establishment of the first secular universities. Whenever that was. Professors were smart to recognize that the world operated on cause-effect relationships, and they eliminated the need for a deity from their weltanschauung. But people who needed to survive by avoiding natural or human-made disasters still believed in superstitions. Secular professors worked in cities, with stable income, the cities were walled so protected from enemy attacks, and there was some medical help available when needed. They felt secure, they did not need prayer. So they cast god aside.
The growing number of proletars and bourgizisaiaidfise (I can't spell French words, with a glee) came a new era of "pretend" religioosity, where people believed in some sort of creator, but they did not depend on it for too much.
This lasted into the middle of the last century, in most of Europe, or to the nineteen-twenties in Russia, where Communism obliterated religions in the main.
The true, unforced era of atheism came with the prosperity of post-war Western Europe. Bellies were full, no war, disease or pestilence. Penicillin was a saviour. Education became free, so did medicine, and so did welfare, unemployment insurance and retirement income. Life became good.
In America, according to this explanation of atheism, the lack of medicare and the proliferation of guns stop Atheism. That's why the strong resistence against gun control and against medicare. People love to stick with their ideologies, it is the strongest force of cohesion between members of the tribe, so it's the strongest social value and the strongest survival value for a community. Their common beliefs.
America is not atheist for this reason. Superstition is a major part of life, to stave off the evil that causes financial ruin via sickness that's too expensive to handle, yet one must pay for it. It can come any time, any direction; it is random. The randomness is what keeps the superstition alive. Because to fight it, you need to appeal to a god, and gods are, let's face it, fickle. They sometimes grant wishes sent to them in prayer, and sometimes they don't. It's completely random. Actually, so random that you almost could say the gods don't even listen... because they don't exist.