According to Chapter 4 of the Sai Satcharitra, why do saints like Sai Baba come to Earth?

Chapter 4 of the Sai Satcharitra explains that saints incarnate during times of significant religious and moral decay. They descend to the world of mortals when people lose their way, becoming obsessed with worldly happiness from wealth, status, and family, and turn away from the ultimate spiritual goal. As detailed in this chapter, saints come to protect the humble, the poor, and the weak, destroy irreligion, and reawaken faith among the people. Their incarnation is described as being purely for the sake of others, with no self-interest involved.