In Māori culture in NZ, tribal elders (kaumātua) function much the same, they are the keepers of knowledge, history and cultural practices for their group(s).

I suspect you'd find the same in many cultures that didn't have writing to transmit knowledge.

(There's also the aspect of "mana", a very hard word to translate, "face", "influence", "power" or "really respected" are good approximations.

A kaumātua with mana accords your group (iwi/tribe or hapu/sub-tribe) with their mana.

So, say your Granddad was a renowned warrior or diplomat, even though he's in his 80s, the respect his opponents developed for him still persists, and flows onto you.)