Humans are a very long lived species already at least when compared to most other large high metabolism mammals. That means evolution already did a lot of optimization for longevity, possibly driven by the high value of grandparents in child rearing and passing on valuable knowledge.

This is also why lots of mouse longevity research doesn’t translate well to humans. Mice are not a particularly longevity optimized mammal so it means there is more low hanging fruit there.

For us all the low hanging fruit is likely picked.