But most religions structure their beliefs so rigidly that there would be conflict with such a movement. Who needs that?
Not in my experience with religion. They are constantly growing, changing and adapting.
Maybe not in a way that every single individual would agree with, but that's an impossible task for anyone, about anything.
Edit: That's why religions have sects and denominations for instance. Examples of how pluralism can work with a large number of different intermingled religions, look no further then India. Not perfect, but as I stated previously, what is?