They did listen eventually. Ashitaka and San were given a proper burial, and were buried in the forest. Moro, Okkoto, Nago, and his wife, Karou, rebuilt the forest as it once was. Tatara was renamed to Yasu, Peace. The sword of Kohai was gone, floating in the water toward an unknown destination.
Eventually, the Emishi people were able to accept Kaya-sama as their queen, and lived – once again – peacefully. The memories of the war had faded. Everyone was at peace.
When Kaya-sama died, Moro took her place as the queen of the Emishi people several years later. Okkoto, Nago, and Karou, and their small daughter, Kiyo, stayed behind.
If you listen closely to the wind, you will hear it tell you the story of Akai Okami to Akuma.
If you listen closely to the wind, you will hear it tell you the story of the Red Wolf and the Demon.