One of the things related to food that I noticed reading the story was that you still need primary food production even in the world of the duplicator, since it duplicates the food exactly as it is, food will still go bad. The duplicate is just as old as the original. Sure, canned beans will last a while so you can keep duplicating them for years, probably, without concern, but if you buy a loaf of bread you will only be able to duplicate it and eat the product for the same length of time that it would usually take your bread to get moldy.
You don’t need much fresh food, but you still need it. I guess you’d get communities of people sharing a single loaf (or slice) of bread to be duplicated, a single apple, etc. Or just a grocer who buys a small amount of produce and sells the right to duplicate it to everyone in town. A baker who makes one loaf of bread. This is similar to the idea of the grocer in the story except the point isn’t the diversity of offerings but just the fact that they are fresh.
The same will be true of goods as well, which wear out over time. You can mitigate this by for instance keeping one copyable version of your shirt in you closet and wearing a duplicate which you replace when it gets worn and threadbare. But even the protected original will decay eventually. At some point, you need a new shirt, not a duplicate of an old one, which will also be old, but a new shirt that’s newly manufactured. The manufacturing process can certainly be made much more efficient with the duplicator, or course (you don’t need to grow fields of cotton, you just need on cotton plant and then duplicate that, etc.)
Which makes me imagine a scenario where this society goes on for a while with everyone just making duplicates of the original stock of stuff and keeping things work pretty well for a while, until one day all that old stuff starts to wear out but at this point no one is alive who remembers how to make it, and civilization is lost. Maybe that’s the fate that the aliens at the beginning were predicting...
Additional to the effect of parental investment on the selection pressure favoring longer lives (and thus a lower rate of aging) in humans, is potentially the effect of grand-parental investment. If in humans grandparents have a large impact on the rate of survival and reproduction* in their grandchildren, then the selection pressure for survival gets pushed to even higher ages, potentially into the ~60′s/70s. The importance of grandparents seems to be relatively unique to humans.
I’ve seen enough evidence (related to the grandmother hypothesis wrt. the evolution of menopause in women) that at least grandmothers still invest heavily and effectively in their grandchildren that this is a plausible mechanism leading to longer lifespans in humans. For instance, survival rates of children with grandmothers in hunter-gatherer societies have been measured to be greater than for those without.
I do wonder if this should lead us to think that aging should be faster in men than women, though given that we all have both a mother and a father, that speculation isn’t entirely obvious to me.
*the importance of things like status and skill transfer in humans means that beyond just influencing survival grandparents might also influence the reproduction rate in their descendants in other meaningful ways.