Noah is the restart of the human race after the whole human race has been wiped out. Abraham, also a new Adam, restarts the human race, begins a renewal of humanity and creation, within the world. He is leaven in the lump. A restart for humanity within post-Babelic humanity is a trickier business than restart after the flood. Noah had the advantage of having a clean slate. Yahweh decided not to do that with Abraham: No clean slate. Rather, He starts something within the race to transform it from within. This is an incarnational move. In Abraham, Yahweh enters into the flesh.
Abraham’s ancestors do not seem impressive. They are not the great men who make a name for themselves at Babel. They are like the descendants of Seth, with no cultural achievements, no cities, no invention of music or animal husbandry. Their history is just names and dates. But the chronology of Genesis is tied to them. They have nothing but time, nothing but the future.