How do Religions Die?

Andrew Brown in the Guardian:
Religion under attack: Hernan Cortez with 200 Spaniards and 5,000 Indians defeats a larger Aztec force in 1520. Illustration:Archivo Iconografico/Corbis
Do they waste away, or get conquered by something better? Perhaps it is easier to think in terms of gods dying, rather than religions

If religions are born, they must also be able to die. How does this happen? I think we can discount at once the idea that it happens because people realise that science is better. It's obvious that the more people try to replace religion with science, the more they reproduce the worst features of organised religion.
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