As a life-history variable longevity has served humans especially well. Extended childhoods not only encourage brain development, it also knits families and communities closer together, as altricial youngsters need resources and protection for greater durations.
Living longer garnered the greatest advantage that a social species given to technological innovation could have: the benefit of experience.
Groups of gregarious mammals are commonly led by elders. Elephants and cetaceans are exemplary. Their knowledge of foraging techniques and prime feeding locations can be the difference between group survival and demise.
The experience edge can be particularly telling in territorial concerns, whether defending or taking new lands. Wolves are predators whose prowl is determined by dominion. Taking territory from another pack is largely a numbers game, but experience tips the balance beyond numbers. Packs with grizzled veterans battle better for territory.
Being physically past their prime, brawn is not the contribution that old wolves give to a brawl. It is instead imparting improved combat tactics to their packmates.