[Capt-RogerOver]

You are not considering the value that very old individuals might contribute (and in fact do so) in many sophisticated societies with language: teaching of younger individuals and also acquiring deep complex knowledge about life, which can be simply impossible to do if they had short lives (they would just not have time to learn any of it). In many times of our history the resources weren't that scarce to begin with. Primitive tribes don't need to dig for rare metals to make their Teslas, they could survive and thrive on very abundant resources.