The sociological response to the ossification of civilization, brought on by excessive longevity, is murder of the immortals. We currently have several septuag

The sociological response to the ossification of civilization, brought on by excessive longevity, is murder of the immortals. We currently have several septuagenarians duking it out to be our next elected executive leader. Imagine the political discord that would exist between generations if all the leaders were over seven hundred years old. We'd be warring constantly over the inequality. If one stays inside, eventually the 20th-generation scion of a human family that they have been collecting rents from all that time comes in to kill them, and free his children from the yoke of their undying ownership. Inspired, of course, by an alliance with their grandchild, who wants to inherit something of their own before they turn 500. It's not that they are cavalier with their lives, as fighting to wrest resources away from their elders, when Death refuses to help. The young have no place to call their own in which to stay. The old cannot fortify against every threat, and must project the impression that they take enough risks to die from their own activities, otherwise be murdered for calcifying local developments. Alternately, an immortal society could have a festival every century in which all property passes to one's living heirs, and the eldest living ancestor, who would otherwise receive no inheritance, is paid some cash by all their living descendants. I recall a story in which people above a certain age were banned from all governing roles, and could only fill advisory positions. Futurama had the retirement planet, where the eldest (a.k.a. Prof. Farnsworth) were imprisoned to keep them out of the way. Even the various cultural mythologies had new gods arising to slay and replace the old gods. It's very well explored--immortals get murdered. Even the Monkey King, who was six-ways immortal, faced execution, and when the gods discovered they couldn't kill him by any of the known methods of killing immortals, they instead put a mountain on top of him to keep him from moving.