Adaptive Reuse of Existing Urban Space for Community Elderly Care: A Tripartite Evolutionary Game of Policy-Dependent Activation and Post-Targeted Maintenance

Adaptive reuse of existing urban space offers a resource-efficient pathway for expanding community elderly-care provision, but physical reuse does not necessarily ensure accessible locations, capable operation, or sustained utilization. This study develops a tripartite evolutionary game involving the government, stock-space provider, and professional elderly-care operator. Effective utilization links spatial accessibility and integrated operation through stand-alone gains and a configuration-generated utilization return, while targeted regulation introduces eligibility screening and differentiated quality incentives. Shanghai provides the institutional context, with Pudong New Area used to construct a case-informed reference configuration rather than an estimated local equilibrium. Results show that quality-invariant basic support can sustain provision without necessarily removing marginal spatial or operational quality barriers. Activation and coordination are sensitive to policy architecture, actor-specific rewards, costs, and the interaction between utilization and policy synergy. Under the modeled separation between basic support and an additional targeted-performance layer, post-targeted maintenance instead depends on configuration-generated utilization returns relative to incremental spatial and operational costs. Here, maintenance denotes local strategic maintainability under a given demand and parameter environment rather than long-term demographic or neighborhood stability. Numerical tests further show that local maintainability does not imply automatic reachability. The findings identify a conditional catalytic-governance mechanism in which targeted intervention can facilitate entry into a maintainable coordinated S1O1 configuration without implying permanent targeted-policy dependence or global convergence.