What near everyone fails to realize is that society is built around death, namely, preventing it.
It is death itself which gives life meaning. If the world were stagnant, then there would be neither challenges nor growth. There would be no purpose. In all religious traditions, humanity's primary goal is to conquer death. Afterlives are an extension of this, as the spirit conquers death, reaching an eventual peaceful existence. From a scifi standpoint, if we were to conquer human death, we would still have other forms of death to conquer - such as the heat death of the universe and the eventual explosion of the sun.
As long as there exists something out there that humanity does not know, there is the potential for extinction of our species or descendants. This could be the presence of multiple realities, universes, things at the edge of the galaxy, or any existential threat to our species. There will, hopefully (in my view), always be something to conquer, or there is no meaning - which sounds callous, but is the truth. Life is given meaning in accomplishing challenges. Very few things that are easy are worth it, and last. We should try to limit pain, but it is the act of limiting pain that is important.
Envisage a life without challenges by imagining the lack gravity. You would be an amorphous blob, or after generations, would at least turn into one. Without gravity, you'd have nothing to push against. You would develop limited abilities to move. With gravity, you can develop muscles and structures. Too much gravity would crush you, but just enough allows you to develop skills that would otherwise never develop. A little bit of challenge helps to provide meaning. Death provides a huge challenge, but it does do that - provide meaning.
That's not to say that other great meanings don't exist. I believe that the second great meaning of life is in other people. But this belief in other people is intricately tied in with conquering death itself. If death didn't exist, if all we had to do was exist as enjoyable forever, then I am unsure whether we would care about others. If we never personally conquer death, we hope that others will carry on what we have accomplished to improve the lives of others within our species, other species, or that of our children.
The point, though, is that everything we as humans do is about death. We would not do nearly everything that we do if it were not for death. We perform a lot of agriculture to feed ourselves, build homes to shelter ourselves from inclement weather, work to provide fuel both for nutrition and shelter, enact laws to provide safety to avoid the worst causes of death, and create hospitals to stop the spread of death. War is about resources to prevent death, which causes death. Even science is to support our understanding of the world, which supports hospitals, war, and is helpful to stop the spread of death. Economies are built around all of these things. Even people who collect vast wealth will use that wealth in their own vain attempts to slow their progress towards death.
You might think, "I enjoy pleasure, and that is my purpose, so I don't think about death." That is in itself an attempt at conquering death.
The great beast of death follows all of us to eventually catch us, even if we never stop trying to conquer it. Perhaps one day we will. Perhaps one day they will say we all died so young at the youthful age of 110.
There is one thing that death causes - life. We create life to also conquer death, and every life creates a new attempt at that conquest. This isn't true just for humanity, but for all creatures great and small. The number of biological processes involved on our planet and even on asteroids just beyond cannot be understood by our finite brains. Yet, every attempt, from virus (if they could be considered alive), bacteria, protozoa, plankton, trees, elphants or humans gives another go at conquering death.
Over the last several million years, humanity has come into existence, and every so often, we keep trying to have civilization. There are campgrounds of settled societies from 80 thousand years ago, that for some reason eventually broke apart. Over the last few thousand years, we've tried the societal experiment with increasing degrees of success. And it's because we find this very beneficial in preventing deaths, otherwise we would never have done it.
But, we have something now that we have never encountered before to our knowledge – connectivity across the whole world. Well, we had this. Animals have migrated, certainly carrying some diseases through flight or water between Europe and the Americas well before Colombus. But we've never had such connectivity of ideas, except between the people who have little acquantance with death that somehow are unfamiliar with the ideas of those who have a daily struggle with it. These ideas spread more easily than any biological virus, yet can cause much more death than any virus.
Ideas compete for life, although unintentionally, as they try to replicate themselves. They "want" to survive. Some ideas can stop other ideas - idea inoculation. It may depend on which ideas arrives at you first as to what takes hold. If a poor idea has come first and you've built your world around that, then it may leave impossible to overcome consequences. Ideas are so important that humans have weakened their infants physically so that an infant can learn all sorts of important ideas over long periods of time. It is also why people invest so heavily in political sports-teams, because they believe that those ideas are important in preserving their own lives.
Ideas are important for preserving life. They say that the pen is mightier than the sword. A well written word can spread and inspire nations, inoculating them from bad ideas, yet be near impossible to track. Communication is just as much about preserving life and fighting death as any of the other things.
Ideas, germs, people, all of them change with each new iteration or passing moment in their everlasting fight against their own death, which somehow provides meaning.