Why are we so preoccupied with extending our lives? Only if we proportionately extend our productivity does it make any kind of sense at all. However, with the worries of hitting ten billion within decades, bringing down the natural death rate will only heighten our overpopulation and sustainable living crises. Furthermore in societies that have achieved below replacement rate fertility without in-migration to compensate for the lack of native youth, the last thing they need are elderly staying around even longer -- they don't have enough young now to support and provide services to a population of aged persons.
On the individual level, those of us who believe in a soul to be reincarnated or have faith we'll be spending afterlife in a heaven shouldn't be concerned about death, because it's just a transition to another and possibly better phase of existence. For those who have no concept of survival beyond bodily death -- why worry? You can't regret being dead if you no longer exist. That leaves the question: Are people so preoccupied with living longer, because most are secretly afraid they're going to Hell? I wonder sometimes. Personally, I'm going to be happy to end all the painful lessons I've had in this life with this autistic brain and hopefully come back as someone or something happier and healthier. I'm just concerned that I fulfill the purpose for which I've been born into this body. If I'm wrong and there's a heaven waiting for me, Whoopee? If the atheists are right and I'm obliterated, then I won't be able to regret my death, in any case. I can't really say that I believe in a Hell any more, unless it would be for those who are unredeemable no matter how many lifetimes they may lead. Hitler, perhaps? But why not give him several million lifetimes as a cockroach?