Oral tradition part is important because otherwise I don't think "people a few millennia ago thought that the maximum human lifespan was in the ballpark of 120y

Oral tradition part is important because otherwise I don't think "people a few millennia ago thought that the maximum human lifespan was in the ballpark of 120yr" follows. You can say "the authors of Bible thought that the maximum human lifespan was in the ballpark of 120yr" or that they're influenced from the public, but that needs further evidence.