Earlier quoted context omitted.
A better way to put is that, without death we wouldn't have progressed as a race as much as we have done. We need new people with fresh ideas to come to top, take higher roles and make radical decisions. People living longer will stay in power longer and keep the status quo alive. In a longer stretch, conservationism, which grows like age, is an impediment for innovation and progress, IMHO.
If we were immortal, the birth rate would decline as people worried less about continuing through progeny and more about continuing through their own lives. How many wars do you think anyone would want to fight if we didn't have an endless streams of the young who are willing to die on the battlefield? How many murders are committed by people over 30 vs under? How many people die in car accidents after 30? There's so…
Would it? In modern, low reproduction societies the dominant interpretation of the universal "honour thy father and thy mother" focuses on care. Even the slightest resemblance to a chain of command that might be present earlier stops at adulthood. But with people forever overshadowed by their undying ancestors, we might see a massive resurgence of the competing interpretation which sees it as a natural power structure. If that happens, well, welcome to pyramid scheme hell.