The Sun and Moon Essence Qi of the Dongyuan Realm was far more abundant than that of the Cangyun Realm, especially the Moonlight, which at night was almost thick enough to be visible to the naked eye.
Such an environment was incredibly favorable for Savage Beasts that grew by absorbing the essence of the sun and moon.
Nowadays, most of the Dongyuan Realm was occupied by Savage Beasts, which wasn't unrelated to this.
Totems could draw Spiritual Energy from the world to nourish the flesh and also absorb some of the essence of the sun and moon, but compared to Savage Beasts, the efficiency was much slower and simply incomparable.
Furthermore, given the totems' short lifespan, even if the Human Race had strong warriors emerge, they could only maintain stability for a moment. Even if they fought for some territories, after a few thousand years, they would ultimately be retaken by the Savage Beasts.