You are right in that generally a whole group does not spontaneously decide to change faiths, but there are plenty of examples of a gradual erosion of a faith i

You are right in that generally a whole group does not spontaneously decide to change faiths, but there are plenty of examples of a gradual erosion of a faith in communities . "The vast majority of U.S. adults (85.6%) say they were raised as Christians. But more than a fifth of them (19.2% of all adults) no longer identify with Christianity." [0] I think a ~ 20% change within a single generation is pretty significant. And most of these people will use the 'recipe' method you describe because it is easier than learning an entirely new system. There are many historical examples of this. E.g. Taoism + Buddhism -> Chan Buddhism -> Zen Buddhism. [0] https://www.pewresearch.org/religion/2015/05/12/chapter-2-religious-switching-and-intermarriage/ https://www.pewresearch.org/religion/2015/05/12/chapter-2-re...