Do you remember the Legend of Quanyin (Avalokiteshvara)?
It is said that he made a pledge to not rest until he had liberated all sentient creatures. Despite the fact that he used all his force, unfortunately there remained too many that he could not save. As a result his mind then split in eleven parts.
The legend relates that the Buddha Amitabha saw this and converted the eleven pieces into eleven separate heads in order to enable him to then listen with success to the suffering of all. He attempted to reach them all, but when he reached out to them his arms were destroyed.
Once more Amitabha entered the scene and gave him one thousand arms to help all beings.
This may be just a legend, but when there is an Awakening in the Realm of Formations then the Awakened one is driven by that nature to help all (not individual) sentient creatures.
While his success with animals always bears fruit, human creatures are so burdened with impediments that the task is impossible. In fact, few individuals really listen.
Most are searching for relief from suffering. Some search for a peaceful way of life. Some search for the Awakening. He cannot help one of these.
Only when with Confusion, Acquisitiveness, Aversion and even Paranoia, the person wants to know why the world of Samsara is as it is, can he or she be actually aided as part of the whole diversified Life Force.
But as the population of the world grows and the diverstity of life is reduced, he sees that the task is growing and his efforts useless although he gives all.
He has only one Natural Function and that is to help the apparent existence of the Diversity of Life.
He cannot ever do this and this is the Spine in his Flesh.
It is through ENLIGHTENMENT that the solution arises.