Each and every experience I've had with people all over the world is that their religion is not just a part of them, it is them. It is who they are and how they view the world. Now, we can talk about the folly in believing in idols, etc, or we can sit back and enjoy the interesting world that exists because different religions abound. I use these particular examples because I think that its easier to see how religion can add to the exotic character of life and how those experiences make our lives more enriching. I think we should work for a society that tries to preserve religion for exactly the same reasons why we want to visit an India, or visit a Nepal, or visit Bali, or visit an Amish farm, etc.
Religion makes life interesting and exotic.
One way to preserve cultures is by preserving the religion that supports it. They will often display their culture as a money-generating gimmick, but that is actually worse than experiencing any culture. The 'facts' that are produced by history, science, economics, philosophy, etc. will influence religion naturally. The key, in my view, is to let this occur naturally so that religion can be preserved while at the same time religion adopts the 'facts' of the world. What we have available that we can all agree on is the special experiences of being human and all the variety and spices of life that being human has produced.