Digital Economy and Aging-Service Capacity in China: Service Availability Mechanisms and Fiscal-Technology Support Thresholds

China’s aging population is placing growing demands on medical care, social protection, community-based provision, and everyday assistance. Using a balanced panel for 31 provincial-level regions over 2014–2023, this study evaluates whether regional digital-economy development is linked to the capacity to meet those demands and how that relationship varies across service and institutional settings. The Digital Economy Index (DEI), Aging-Service Capacity Index (ASC), Daily-Life Service Availability (DLSA), and Healthcare Resource Availability (HRA) are constructed with pooled entropy weights. The Fiscal-Technology Support Intensity Index (FTSI) averages standardized fiscal-expenditure and science-and-technology expenditure intensities. The empirical strategy combines province and year fixed effects with alternative index definitions, lag structures, Oster bounds, and two-stage least squares checks. Indirect-pathway, interaction, and panel-threshold models are then used to assess service availability and fiscal-technology conditions. The preferred estimates indicate a positive within-province DEI–ASC association. The estimated indirect associations through DLSA and HRA are both positive, suggesting that daily-life service networks and healthcare resources are relevant pathways. The association is also stronger at higher FTSI levels and above the estimated threshold, with a similar pattern under the per-capita FTSI_pc measure. Overall, digital development is more closely associated with sustainable aging where local service systems and institutional support can translate digital resources into accessible services.