Why do people's focus on worldly happiness trigger the incarnation of saints, as explained in Chapter 4?

According to the teachings in Chapter 4, a saint's incarnation becomes necessary when humanity loses its way by prioritizing transient worldly happiness over spiritual goals. The text states that when people consider wealth, status, sons, and spouse as the only source of joy and completely turn away from the thought of the ultimate goal (Paramartha), they lose the chance for ultimate well-being. This decay of religion and obsession with lust and hunger prevents self-upliftment. Therefore, as Chapter 4 explains, saints incarnate to reawaken religion and remind people of the path to true, lasting happiness beyond the material world.