The Temptation of the Elves
My fellow obsessive Tolkien fans may recall Tolkien's speculation that, just as Men seek relief from death, Elves might seek relief from deathlessness. That seems a bit odd, but I think he meant that Elves might seek relief from change. You may recall that the Three Rings were intended to preserve things unchanged.
One effect of longer life spans is that most of us will see far more change in our lives than in earlier societies and we're not used to it. Anyone my age (or even a bit younger) will have the impression that “they're changing the rules every few decades.” This can be upsetting and it's understandable that many people will try slowing it down. Just when you think you know how the world works, you find that you can't get a good job any more right out of high school … or that your favorite restaurants and stores are closing … or that you have to learn how to decipher a new set of accents or ….
This may explain the efforts made to keep newcomers out of countries or neighborhoods. Please note that if you try using the One State, it's like using the One Ring. It's nature is evil and it consumes those who would wield it. For example, if you try keeping people out of your “backyard” by growth controls, you produce a zero-sum game and any newcomer will push out those stores that you want to keep.