Building a Sustainable Social Safety Net: An Integrated Framework for Inclusive Growth by Unifying Economic Incentives, Social Equity, and Governance Accountability

Under the dual pressures of global population aging and fiscal austerity, the sustainability of traditional social security systems is facing severe challenges. Existing policies often fail to achieve sustainable inclusive growth due to the fragmentation of economic incentives, social equity, and governance accountability. To address this challenge, this paper constructs an integrated institutional framework that endogenously integrates marginal pricing, rule-based redistribution, and on-chain accountability mechanisms, aiming to achieve sustainable development across the social, economic, and fiscal dimensions. The study employs a heterogeneous agency life cycle model and conducts numerical simulations to compare three scenarios: baseline, inclusive, and compatible (which incorporates "tax-wealth—targeted transfers"). The results indicate that the framework achieves an inclusive effect of "supporting the bottom without harming the top" while ensuring fiscal sustainability: In the inclusive scenario, the variance in wealth shares of the poorest 10% of the adult population converges by nearly 16%; In the compatibility scenario, their disposable income increased by over 100% compared to the baseline scenario, while the standardized Gini coefficient decreased from approximately 0.36 to 0.25, a reduction of over 30%. Both scenarios ensured the sustainability of fiscal resources through positive net growth.