I think you've got this backwards. People are inherently religious. We evolved to see intent behind everything. Post hoc ergo propter hoc is psychologically powerful.

"Why has it not worked?" suggests that atheistic societies have arisen and they've failed. That's not the case. Atheism has just been historically very unpopular. It's only recently that science has advanced enough to put the "god of the gaps" in a sufficiently small box for atheism to arise on a large scale.

I think, given the knowledge available to us now, religion is obviously fiction. The only difference between worshipping Jesus and worshipping Harry Potter is that the former's authors are very long dead.