When the return on effort collapses—when a young person must work longer hours for less net income, less housing security, and less ability to form a family—the rational response is to reduce engagement. Tang Ping is the cultural expression of a demographic and energetic calculation: if the marginal return on participation is falling, and if the accumulated claims of the old are extracting an ever-larger share of the shrinking surplus, then the optimal strategy for the young is to minimise their exposure to the system.