Have you read Oryx and Crake by Margaret Atwood?
Another reason for the big fall in Christianity in America is that it requires you to obey God, and many people don’t want that, as society has become more and more individualistic. It clashes with self-determination in life; people don’t want God to run their life.
Not sure how this could be proven, but I believe that there are many religious sects and communities (could be many or most, but I’ll just say “many” for now) that are basically incompatible with critical thinking – thus, if more people learn and apply critical thinking skills, then they will be “unavailable” for many specific religious groups (i.e. fundamentalist groups, Biblical literalists, etc.).
Actually that’s a much more valid point than I think you meant it to be.
I come from a university (Texas A&M) with a VERY fervent fan base (some might say insane, rabid, loony, etc…). And we have a very active and large alumni organization as well. And being a formerly all-male, military institution located in the sticks, we have a shitload of strange (from the outside) traditions. Among them is the notion that “Once an Aggie, always an Aggie”, meaning that we’re all part of a greater community of current and former students- not necessarily graduates either.
For some of us, it’s stuff we did in college and was fun then, and now we identify as nominally part of the community, but mostly as whatever else we do.
But for a lot, this whole thing takes on a quasi-religious character. As in, the world revolves around football season- I swear some of them would plan funerals, weddings and births around A&M football games. And their personal identities are VERY centered around the notion that they’re Aggies. Very defensive of the school and it’s traditions, even when they may be harmful or not in the right- it’s very much got that same sort of circle-the-wagons insular mentality that religious organizations often have.
I view it as something of a desire to be part of a community that’s enduring and shares similar views. Even the hyper-religious among us are fervent Aggies- I suspect it’s the more mobile, less firmly rooted society we have today- identifying as a Baptist doesn’t give the same warm fuzzies or feeling of community when you live in Dallas, your parents live in Beaumont, one sibling lives in Houston, one sibling in Austin, and your aunt/uncle/cousin lives in Lubbock. But you can all be Aggies and all be part of that same extended community.
I’d be really curious to see if things like that are becoming more prominent in people’s lives or not- it seems to me that looking at my dad and uncle’s opinions about being Aggies (proud of it, but it’s not their primary identification, and pretty laissez-faire about most of it), and then looking at the younger, more rabid Aggies of my age and younger and wonder if that’s what I’m seeing.
You may be right, but… have you applied critical thinking to this belief? Do you have evidence? Or are you saying “Not sure how this could be proven, but I believe that there are many people who believe things that can’t be proven”? 
Requiring a belief in God for membership, saying obviously Christian prayers, having a chaplain lead the organization in prayer seems pretty religious to me as a deist, not even an atheist or agnostic.
Touche!
Why?
Do you need a concept of a digital watch in order to have an analog watch?
Do you need to have a concept of any sort of watch in order to meet somebody at sunset?
I believe this is what Vonnegut had in mind in Cat’s Cradle when he invented the term “granfalloon.”
But if there is no deity, all granfalloons are false karasses.
And Vonnegut was an atheist.
I wish he’d written more about Bokononism, personally. I’ve found it very useful. Foma, of course. But useful foma. 
Nice, nice, very nice!
Looking that up, that definitely sounds about right. Anyway, I suspect people are substituting these granfalloons in place of organized religion, or in some cases, conflating them with organized religion (evangelicals and the GOP).
Either way, it’s not like people have fundamentally changed, or that there are enough “out” atheists out there to have affected the church attendance rates, so something else is going on- people will still want to be part of something larger than themselves, so if church isn’t fitting the bill, what is? I’m nominating the granfalloons of modern society as filling that void, however imperfectly.
So what will replace Christianity as a moral authority or belief in a higher power?
Tbh, I actually see this less and less (though, obviously this is anecdotal). Seems like people were far more prominent about the community surrounding sports teams years ago than no. I see more people make fun of folks who get THAT into sports - because generally the primary identification folks tend to have a corollary of that the team/fans that they HATE. I know one person who identifies so much with being an Atlanta sports fan that he HATES the city of New Orleans and anyone who is a Saints fan. We mock him for this.
In some respects it’d be similar to the Baptists who loath Catholics for “not being Christian”.
Anyways, I always get a little sad at these discussions because it seems like more than a few people say, well if churches were more liberal and tolerant this sort of things wouldn’t happen. Or that maybe this will be make churches more tolerant. As if Liberal Protestantism (or Liberation Catholicism) simply doesn’t exist. There are millions of people in various progressive denominations - Evangelical Lutheran Church in America, The Episcopal Church, Presbyterian Church USA, etc. But not only are they completely ignored in these discussions, but are losing members (so are the conservative churches mind, but the liberal churches started losing members earlier).
Does the latter need replacing
Fair enough, and thank you for the additional information. I stand corrected.
In healthy adults, moral authority comes from within.
Belief in a higher power is not necessary, any more than belief in phlogiston or belief that bad-smelling air is the cause of malaria.
You seemed to be on the verge of making an interesting point here (not sarcasm) but kinda let the thought peter out without making a conclusion. Yes, I should have realized when I was posting the Jubilee Church story that other liberal churches are struggling for membership, too, as you have noted. Why do you think this is happening and can you relate it to the thread in a more specific way?
The liberal churches are losing members because they don’t have a solid value proposition: They’re a social club where you have to believe in a specific bunch of weird things and discuss the same book? It’s more fulfilling to join a D&D group or have a stammtisch at a bar that has trivia nights. At least with those options, you don’t have to pretend the make-believe is really real. For something more explicitly spiritual, you could join a Unitarian church, at which point you’re no longer “Christian” to the extent Christianity is defined by a set of dogmatic beliefs held by its members. You’re just going to a place to be vaguely spiritual with other people who may or may not believe as you do, or believe anything at all.
Honestly, I think part of the decline of religion has to do with the destigmatization of mental illness and therapy. If you can get treatment without the dogmatic/cultural baggage, and that treatment has to at least nod at being evidence-based instead of being, at best, non-specific sub-talk-therapy-grade platitudes and, at worst, guilt-based and fear-driven, you’re going to take your neuroses to a professional, as opposed to “receiving guidance from a spiritual leader”, as a Boomer might phrase it. Look, I gots me a cite an everything! (It’s a blog, but it seems to be commonplace enough that Millennials-and-younger talk about mental health pretty openly. I hesitate to cite to my own experience, but it rings true.)
So: The liberal sects are moving with the times, and embracing social change, but they don’t offer anything hugely new, and they don’t offer “talk therapy without the stigma”, now that actual therapy has lost its stigma. The fire-and-brimstone insane-o shit offers something different from what the rest of the world is doing, but what it offers is insane-o shit which will isolate you in a world moving away from consensus reality and, quite possibly, towards a burning compound or shootout with the FBI or suicide pact enforced by armed true believers in some town nobody’s ever heard of.
If I did, I’d be the darling of the ELCA ;). I think it petered out because we are at a bit of a loss about it. The conservative churches seem to point to liberal Protestantism losing members as an indictment of liberalism in the Church and see it as validation that liberals are basically secular humanists. My thoughts are not super dissimilar to the problem - perhaps that a lot of people in liberal Protestant churches don’t really see much of a distinction between us and the secular world, so why keep going on Sundays. What to do about it is where the distinction comes in. Conservatives think liberal Prots should accept conservative Biblical interpretation. My opinion is that liberal Prots should make clear that social justice action is done due to our interpretation of our faith (kind of like what happened during the Civil Rights Movement - MLK was never shy about talking about God). But while that has started to be done more (William Barber comes to mind and the Presiding Bishop of the ELCA, Bishop Eaton, as well as Bishop Curry of the TEC), I don’t know if it makes much dent other than secular liberals saying “This is what Christians should be like” and then just ignoring us again until we make news again.
I may be validating the conservative churches’ criticisms, but you don’t really have to believe in all that much as a member in most liberal Protestant churches. We definitely have our share of agnostics in the pews. We don’t think doubt is a bad thing after all.
We do discuss the same book, however. And the leadership generally believes in the specific bunch of weird things (the leadership is also substantially more liberal than flock - at least in my denomination it is)