Knowledge

The very point is: If one could pass his knowledge to the next generation by language, being able to live longer would be a distinct advantage in terms of competition with other species. The longer you live, the more experience you could accumulate and the better you could enlighten the youngsters.

No, you do not need everyone to live longer. In the setting of small tribes and communities (alas, the structure of early human society), to say the least, a few seasoned members would be highly valued and could often give important advise for the survival of the whole tribe - for example, in the situation of having an exceptionally bad flood or drought.

It therefore goes without saying that when two similar species were competing in places with a harsh environment, the one that could attain more knowledge and pass to its next generation excelled.

That's why our tradition have so much respect to the elder generation: experience !

But, friends, lend me your ears: With the development of a written language, the rule of our game changed. In fact, it was fortunate for the Homo sapiens that the Neanderthals had not invented some kind of words. Otherwise, we should be the extinct species !

PS. Modern men developed written language some 4000 years ago, long after the Neanderthals were wiped out by us.