average lifespans and maximum lifespans are not the same. even in terms of historical averages we're still actually fairly long lived comparatively speaking, even among simiarly sized predatory mammals. the issue with selective pressures however is they are primarily "concerned" as it were with survival as it relates to the species, the ability to effectively and efficiently reproduce. survival of the individual past that point isn't strictly necessary which is how there can be so many prefectly successful species which just outright die after reproducing. we don't bear thousands and thousands of young at once or even litters of a dozen so there is an advantage to us being around for awhile to rear children but as a species with such a comparatively small window for reproduction against long and rescource intensive gestation and maturation periods after a point theres little opportunity for direct pressure towards individually long lives too much past breeding ages. 30 years is just enough for a human to reach maturity and pass on genes while ensuring some offspring also survive long enough to be biologically old enough to do the same. any advantages from social dynamics after the ferility window such as longer lived inviduals in a family unit sharing those genes conductive to longer lives could have an edge over shorter lived ones if older members of the group are still contributing to younger members success and survival are more incidental and far less direct. males having a larger window for reproduction could also be a contributing factor to gradually selecting for longer lives. assuming it's not just advancments in medicince being more advanced socially making those indirect benefits more tangible could be why our maximum lifespans are already a good few decades longer than the members of our closest primate cousins raised in captivity who are also receiving the benefits of medical treatment, consistent diet, and less stressful living.
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