The wars, the philosophy, the worries of our legacies, everything will be gone in less time than more. The sun will make the Earth inhabitable in about one billion years (if not earlier) and then all of human existence will eventually be wiped out when the sun engulfs the Earth when it supernovas. This is why it is best to realize there is no ultimate meaning to life, and to make your life's purpose to be as mentally/physically/emotionally happy as possible. Even then, it won't matter - but, hey, why make life more difficult than it needs to ?! https://phys.org/news/2015-02-sun-wont-die-billion-years.html
I'd say meaning isn't evaluated solely at the end of existence. Yes, right now is important, and we shouldn't continuously postpone our happiness, but we also shouldn't neglect our future happiness. I would also say that we have a duty towards others, we should strive to make others happy, partly because in a society in which agrees to that, everyone will be made happy, partially because helping others can make you happy, and partially because their happiness matters too.
