Yes, this is exactly what I was talking about. We do see bigger churches in the area thrive from time to time, but mostly (and this is going back to my almost forty years in and around the church), but they almost never maintain that kind of staying power beyond the emotional needs of their members. Those folks don’t seem to want steady or mundane, instead it’s all about feelings and highs and ‘what are you doing for me’ type Christianity 101. And with that kind of roller coaster, well sure, you eventually gotta get off.
I’ve found as I’ve gotten older, wiser and more awesome that casual predictions are more often a statement of a person’s fears or perhaps a convenient way of framing themselves as beleaguered. We believe things that cast our stances in the best light. A good way to check this inclination is to gather facts and statistics, while trying not to cherry pick. If they contradict my preconceptions, that’s great. It offsets some of my ignorance. I do that more as I get older. (Coincidentally actually: more aging has been correlated with a deeper internet.)
More seriously, it’s interesting that the 19th c. triumphalist narrative hasn’t quite set in. Implicit in your story though is rising secularism, rising fundamentalism and falling mainlinism outside of Islam. Do I understand it correctly? I’m guessing “Annihilated” is too strong if you count the Unitarians for example. Quite a few people are squishes after all, and religious institutions have some pretty solid social advantages.
It might be interesting to look at religious trends in Brazil. That country is large, multi-ethnic and rich enough to have a secular-friendly (and evangelical friendly) middle class. But it also has a number of competing religious influences.
I just want to note that when people say “African Churches” they should not include the Church of the Province of South Africa, which falls somewhere in the middle on gay rights, depending on which archbishop is being quoted at the time…