They needed to heal, but could only do it from the physical level. This is why humanity was so important. Humanity itself would be the key to healing the universe as it allowed passion, love and Will to be exerted all in one shell. The genetic makeup was key. This is why they focus so hard on the bloodlines here. The problem was that the hybrid ruling elite were stuck in an old programmed pattern and loop of control and self destruction. As it is said, they modeled their behaviour on their former masters, yet those masters have changed. Everyone is exhausted.