Apparently not enough players.
Just like it's easy for people to come to the forums and whine about how their pet religion never got powerful enough to tear down entire realms.
That's a very good question. (Assuming I can parse that correctly...) I've often wondered why, if there are so many people here on the forum complaining that no one (other than them) takes religion seriously enough, they don't all get together somewhere and make a religion that they actually take seriously.
The reason that most religions, even the ambitious ones (especially the ambitious ones?), fail to inspire and take hold is the way they are founded. Almost every one of them has the same basic pattern: Some noble rediscovers and ancient religion that used to really big and powerful at some unspecified time in the past, and brings it back. They work hard to create some huge mythology with funny names, and then hand it all en masse to the world as a fait accompli. The entire thing is a completed work, and everyone is expected to study it, and go along with everything that it says, and that's the end of it. No one else bothers picking it up and running with it, because it's not their creation. They're not invested in it. Someone else made it, so it's their responsibility to shepherd it and make it grow. Other people don't want to keep referring back to the wiki to figure out how to spell, for example, Tlaxacoaltitchili-whatsis, so they can swear an oath on the battlefield to the god of war, famine, headaches, apple pie, and the color blue.
(No offense intended with that example. Seriously. You put an incredible amount of work into the Cult, and it's unfortunate that it didn't survive. But the titles you used are so outside my experience, I don't think I could ever get used to them, and thus could never really get into it as an IG organization, let alone trying to become a serious member.)
IMNSHO, that's one of the things that the founders of SA did that guaranteed its success. (And no, I wasn't one of the founders. I didn't get to join for several weeks after it was founded, because I was stuck doing region maintenance, and drafting soldiers... 
But there are only two or three people left that have been in SA longer than Brance.) Yes, it was the only religion on the island at the time, and that helped. But we ran up against other religions before we could spread too far. The Seven right next door in Springdale had quite a few adherents. As did Torenism over in Everguard and the Libero Empire. Plus VE in Caerwyn stopped us cold for several years.
Crap...I drifted away from my point a bit there...
Anyway, what SA did right was that it did not pre-define an entire mythology that it expected everyone to pick up, learn and be enthusiastic about. It used a very simple concept that you could learn as fast as you could read "Austere, Auspicious, Maddening". (OK, maybe a little longer if you needed to look up the definitions of Austere and Auspicious, but still...) Jesse (the player of Deverka) nailed it dead on. And Rick's (Mathurin's player) move to continue along in the same manner of letting the people in the religion develop it, with very little guidance from the top, played right along with it. The simple concept of three stars, each with a simple defining aspect, and nothing else let people feel like they could pick it up and contribute to defining what it is, and what it would be and grow into.
We still have the occasional massive theological debate over the nature of the Stars, the various aspects, etc. Just recently we had a big debate over the possible existence of a fourth star, or the Dark Star, or whatever it was called. That's the kind of stuff I've never seen in any of the predefined packages that most players try to impose on their member nobles.
The key points, as I see it, that lead to SA's success:
- Simple names
- Simple concepts
- Room to grow and for new people to contribute in a meaningful way to the theology
- A willingness to take a friggin' stand on religious matters, instead of "can't we just cooperate and be friends?"
- A few players willing to actually subjugate their influential characters to the faith, instead of demanding the faith do what they wanted.
Those last two items are at least as important, if not more so, than the others. Brance wasn't set on killing Caerwyn. He thought that perhaps if we could force a regime change in Caerwyn that they could be allowed to live, and Allison could be sent to colonize Flowrestown instead. But the Elders of SA demanded that the new colony be in Golden Farrow. Brance had no choice but to go along with it. The Elders of SA were willing to stand up and tell a realm (multiple realms, actually) what to do, and our leaders were willing to go along with it and do what they were told. Even though two of us thought that perhaps that was not necessary.
I agree. You have to have good circumstances. I think that the right players, with the right concept, can make it work. But not enough people are willing to do what it takes to make it work. Too many new religions are just the same old realm-supporting faith with a new name and a new set of gods. And the players in the realm know this, and only pay it the minor lip-service they need to give it in order to get on playing "the realm game".
Adding new game mechanics to force players to be in a religion, or to give religions a bit more power to hurt regions, is not going to change anything. It will only reinforce the same bland, realm-centric empty shells that we've seen so often. You simply cannot force people to be active, willing participants in the religion aspect of the game.
I'm not sore that the Blood Cult didn't progress any further. I shut it down myself because I had gotten bored with it. I consider it a success, really. It attracted many very active people who contributed to establishing a great library of RP and IG dynamics. It failed when it started losing members as they got executed or as the players left the game. At which point, I never managed to renew the membership with other such ambitious and active people. Indeed, I can't really seem to find any ambitious and active people anywhere anymore, for whatever purpose.
As for SA, I don't buy it. "Blanks for people to fill" are, in my eyes, pretty much "blanks forever so as to not ruffle any feathers". May as well praise Eretzism for "leaving blanks for people to fill". SA still doesn't have a vision on the afterlife, as far as I know, which would be the
number one concern of any religious person. All it has is vague theology that doesn't really force anyone to do anything they wouldn't like to do. All can basically "worship" the stars in whatever way they wish. In my eyes, that's a hollow religion. Follows the same mold as all other "successful" national religions on other continents, except that it came first on the continent, and in a theocracy that would eventually colonize a lot, and at a time where the metagame was really pushing for religion to be taken seriously. That doesn't make it a good model, in my eyes.
As for fewer old religions... A lot of them died on BT. I don't see any improvement.
