General Discussion

But I think it's origins are simpler than that. I believe religions had developed to explain the world around us, since humans didn't have that capacity yet. The Romans had many gods to explain every facet of life. Ancient societies had human sacrifices to please "the gods" or to poison rival tribes. All because we lacked the ability to explain the natural world.
As humanity progressed, and science became more prevelent, there became less and less need to invoke dieties to explain the unknown. Science offered testable, repeatable solutions and answers.
Sure, religions are still pervasive because they are ingrained in the human mind to some extent. Now, your hypothesis is prevelant. But it is also fading from society as scientific understanding advances.
But religions continue to fight back. One only has to see the hostility to biological evolution as evidense of this push back. The religious are afraid of actually knowing where we came from (evolved) so they continuously indoctrinate in their belief system to attempt to explain humanity. Only their "stories" and claims are all nonsense.

So you are correct, the human desire for eternal life is very strong, because humans just can't accept the fact we are but very brief beings on a microscopic spec of dust in an unimaginably huge universe. We're lucky to be here, but in no way are we special.