I agree with your observations and disagree with your conclusion.
Religious fundamentalism is strongly inversely correlated with size of the group. A small religious group will either fail to attract converts (you never hear of those, except if they’re Westboro) or grow. As it grows, it gradually reduces its degree of tension with the surrounding society to accommodate the growing range of interest of its more numerous members. It thereby becomes both more mainstream and more boring, which makes it harder to attract converts. So religious groups, after they attain enough size to become mainstream, grow mostly at their own rate of reproduction. If you doubt this, here’s a list of relevant literature.
Therefore, the mainstream religious movements of the next centuries, besides the shrinking ones we know, will be some of the ones that are now small, having grown to a size where they can’t maintain group cohesion on the oddities that make them distinct. One church that has been making this transition in recent years is the New Apostolic Church. I expect the Jehovah’s Witnesses to go the same way soon—they’ve been de-emphasizing their most characteristic quirks for a while, while maintaining steady growth by telling female adherents to be fruitful and avoid higher education.
There’s also the inverse relationship too—as religious groups lose members, they tend to get more extreme beliefs as a group as the more mainstream members leave earlier.
I agree with your observations and disagree with your conclusion.
Religious fundamentalism is strongly inversely correlated with size of the group. A small religious group will either fail to attract converts (you never hear of those, except if they’re Westboro) or grow. As it grows, it gradually reduces its degree of tension with the surrounding society to accommodate the growing range of interest of its more numerous members. It thereby becomes both more mainstream and more boring, which makes it harder to attract converts. So religious groups, after they attain enough size to become mainstream, grow mostly at their own rate of reproduction. If you doubt this, here’s a list of relevant literature.
Therefore, the mainstream religious movements of the next centuries, besides the shrinking ones we know, will be some of the ones that are now small, having grown to a size where they can’t maintain group cohesion on the oddities that make them distinct. One church that has been making this transition in recent years is the New Apostolic Church. I expect the Jehovah’s Witnesses to go the same way soon—they’ve been de-emphasizing their most characteristic quirks for a while, while maintaining steady growth by telling female adherents to be fruitful and avoid higher education.
There’s also the inverse relationship too—as religious groups lose members, they tend to get more extreme beliefs as a group as the more mainstream members leave earlier.