The truth of the matter is atheism has been around as long as christianity, if not longer. But it has never had natural selection on its side. It is sort of stuck as a minor subspecies, that lacks selective advantage. This opposite is true for Christianity with history showing natural selection.
According to evolutionary theory, breeding rates also reflect natural selection, with religion promoting breeding and atheism promoting abortion and birth control. Even at the unconscious level, nature has decided what is natural for selection, and what is unnatural and needs to be aborted.
I am applying evolution, which is accepted dogma of the atheists, which they don't realize is not flattering to them.
As far as Jesus or not, this belief did create a selective advantage for many humans as demonstrated by history. This was both as a whole and its many parts like England, France, Spain, Germany, as well as the USA.
The biggest atheism experiment of all times, was Stalinism, which did not work out too well, since atheism is paranoid and lacks tolerance. Unnatural selection was given a try, via force, but it self aborted due to natural selection. Once the old Soviet union was broken up ,the paranoid atheists dethroned, and religion restored, then there was prosperity. Now natural selection is natural again.