Sustainable Provision of Community-Based Eldercare Facilities in High-Density Cities: A Four-Dimensional Spatial Evaluation Framework Integrating Governance, Market, and Users

Population ageing challenges the social sustainability of high-density cities, where equitable eldercare access underpins SDG 3, SDG 10 and SDG 11. In China, rapid expansion of community-based eldercare facilities (CEFs) under the “90-7-3” framework has produced a tripartite system of government, operating enterprises and older adult users whose spatial priorities conflict, threatening both distributive equity and long-term operational viability. Existing single-dimensional evaluations inadequately capture this complexity. This study develops an integrated four-dimensional spatial evaluation framework—supply–demand accessibility, spatial equity, functional diversity and market competition—applying the Gaussian two-step floating catchment area method, isochrone-based service-area analysis and a preference-weighted Shannon index to 697 CEFs across 130 sub-districts in Beijing’s central urban area. Results reveal a pronounced core–periphery divide. For service-type CEFs, 90.17% of communities (87.95% of older adults) lie within a 15-min walking catchment, yet service-area overlap reaches 199.32%, indicating redundant resource deployment and intense localised competition in core districts. For residential-type CEFs, only 53.91% of communities are within walkable reach and total coverage drops to 15.84%, exposing care blind spots and spatial inequity in outer districts. Functional diversity, by contrast, is evenly distributed and micro-environmentally shaped. The framework offers replicable diagnostics for sustainable ageing-in-place provision in rapidly ageing high-density cities.