No matter what, religion will stay, not will it stay, billions of people will still be religious. Why? Because of the impossible. When your brother dies in a car crash, would you think, he died, his heartbeat is gone, so is he, just gone, his thoughts disappear. Well that's when religion comes in. Why send him nowhere where you can send him to god, the one that created us, must bring us to an end. He is alive, his soul is alive. He is in the sky, watching me and my family. Protecting my kids, my wife, my loved ones, because he is my brother, he would do that, and he did, and so he will.
People can't accept the hard truth that everything and evereyone must have an end, so they will create some imaginary cults to reinforce their huge egos, because that's better than being humble and accepting your mortality and growing as a person.