Well there's the answer right away, as Kevin Smith aptly points out in Dogma, it's a lot easier to change a belief, if it doesn't work if it feels wrong if something changes to the enviroment then the belief can be retroactivly adapted.
Religion can't do that as easily, you are trying to apply lessons learnt a long time ago to modern day society.
The lessons are still true but now armies are equipped with more then slings and swords, civilisations can be wiped out at a touch of a button without even having to meet with the other side.
How then can we apply a lesson about two soldiers fighting in the front only to discover they are twins seperated at birth?
This is why religion is losing, to be believed to give the will and strength of faith to the follower it can not adapt, it has to "hark on" about how things were. Yes it can be modified to have relevance to current situations but deep down in the darkest region of your heart you know that the moral of the story is still old news.
People don't want to have faith in things that happened a long time ago to people who are now dead, they want to know about how things are just now and what is currently affecting them.
A lot of "new age" and "alternative" beliefs do just that, they give the followers the spirit of faith and the belief to use it.
Personally I like traditional faith, it's what I believe in.
Now the $64,000 question, is there anything "wrong" in not following a traditional faith?
No, there isn't there never is anything "right" or "wrong" simply opposing points of view.
But there is a problem with "alternative" beliefs, and that is that most have a vauge sense of morals, this can be a good thing as most morals are also out of date.
But a rigid defined set of morals no matter how out of date, no matter how bizzare they may seem are still a set of guidelines to be followed and this is always a good thing.
When I started writing this I thought by the end I would have a conclusion of some kind, but there isn't one as such.
The conclusion here is one you have to make yourself, I know what I believe...