I think longevity is a bad goal. No matter what you achieve, it won't be enough, and in the grand scheme if things it doesn't matter (and is probably a net negative, socially). Hundreds of thousands of people are born every day, and hundreds of thousands die. It is the natural way of things for older generations to die so that younger can prosper.
Hard disagree. Many great people throughout history didn't complete the great works they were remembered for until they were in their 50s or 60s. Some even kept doing cool stuff well into their 90s. If we can keep our health and faculties that long and beyond, civilization will continue advancing and providing a higher quality of life all around. We lose so much experience and hindsight with every death. That experience could, for example, be used to make larger populations sustainable.
But you're also assuming that people aged 50+ are necessarily inclined to keep contributing to science and passing on their "wisdom" (quotes because they're actually fallible) to the younger generations. In reality, the vast majority of them would just go on to consume, while also being content enough to be prepared to die any minute.
And believe it or not, whatever knowledge or discovery you think you're losing with one death isn't actually contingent to that person. Given enough time, someone else will figure it out, and it becomes especially less valuable if you believe that AI tools are only going to get better.
More people and longer-lived people also means destruction of nature. We have already eradicated so much, so I also agree that longevity is a bad goal.
