Eh, both of them collide & integrate 1 other all the time. A Japanese Buddhists won't do what Burmese Buddhists do, so does the Italian Christians won't do what British Christians do. Doctrines may intact but it's not that people there will do it because it differs than what they have been doing. Unless they're being forced to, but then it takes centuries or thousands of years to fully integrate them. Like what the people here say "Some meat only like some medicines" Means "Just because it works for someone doesn't mean it works for everyone"
I don't mean to insult those who put their faith in a holy book, but if God is infinite, then the Word of God should also be infinite, and therefore impossible to contain in a work of literature, no matter how close it comes to the Primordial Truth. It isn't something that can be explained to a person, the pieces can only come together through study, meditation, and the divine enlightenment.
Yes, there is purpose and truth in the Bible and books like it, but instead of being the whole truth, it's more like a piece of the puzzle, or looking at a single side of a die. It's valid, but there's also symbolism, things that are implied but not actually stated, and maybe a missing piece here or there keeping it from making as much sense as it potentially could.
To the best of my knowledge, there's nothing actually written in the Bible that claims it's the complete and literal revealed Word of God, in spite of their insistence that it is. In fact, it's impossible to take the Bible literally, because even most conservative Christians can recognize and admit to the use of metaphor. I guess fundies are the only ones who would be insulted by my comment.
I believe each religion is only suitable for specific people for specific era. humans morality evolve. I will give you silly example. there is a cannibalistic tribe. then there is religion founded, which says that eating humans is wrong, but say nothing about eating animals. as time goes by, this cannibalistic tribes leave their habit eating humans. but it shouldn't stop there. once they know why eating humans is wrong, they have to start to think whether eating animals is correct, even if it is not taught in their religions. and so on. humans morality, consciousness, and way of thinking will always evolve. that's why no religion is intended for all people for all eternity.
If it worked then it probably works now. That and the preservation of the state of society. If a society is doing good and happy what is there to change? However once things are going bad, it is either because we rely to much on tradition or not enough on tradition, something must be changed.
Tradition is just the customs and beliefs shared by members of a religion, passed on over time. Tradition does have a particular meaning in, say, Catholicism that is slightly different from other Christian sects or non-Christian religions, but the role and function is more or less the same. One may also have tradition without being a traditionalist, more flexible in changing those traditions or willing to question. There is also Traditionalism, which is more related to Perennialism, which is sort of related but not really quite the same thing.
I know, right? I've got a whole shelf of relevant literature, though I'm yet to read most of it. In English, there must be a lot of works from Frithjof Schuon, Seyyed Hossein Nasr, Titus Burckhardt and James Cutsinger.