Can innovation-driven productivity mitigate infrastructure spatial inequality? Evidence from 282 prefecture-level cities in China

Spatial inequality in infrastructure remains prominent under China's urban-rural dualism and regional imbalances during high-quality development. This study investigates whether innovation-driven productivity (IDP) - a core socioeconomic driver for shared prosperity - can mitigate infrastructure disparities. Employing TOPSIS modeling, inequality indices, and two-way fixed-effects analyses across 282 Chinese prefecture-level cities, we reveal: (1) National IDP levels show sustained growth, with eastern regions maintaining leadership in both magnitude and growth pace. (2) Infrastructure spatial inequality (ISI) follows an initial increase then decline, featuring pronounced early-stage regional disparities characterized by a “high in the north, low in the south” spatial pattern. (3) IDP development exhibits a significant inverted U-shaped relationship with ISI, initially exacerbating then alleviating disparities. (4) Heterogeneity analysis identifies distinct impact mechanisms across developmental stages and geographic regions. By demonstrating how IDP's effects vary spatiotemporally, this research provides practical guidance for optimizing land and space resource allocation, enhancing spatial fairness and justice, and promoting regional coordinated development. The findings inform targeted policy strategies that harness innovation dynamics to reduce urban-rural divides, support phased infrastructure investments, and ultimately advance shared prosperity through spatially adaptive governance approaches.