A System Dynamics-Based Multi-Objective Optimization Framework for Coupled and Coordinated Development Pathways Between New-Type Urbanization and Rural Revitalization in China

Improving the coupling coordination degree between new-type urbanization and rural revitalization does not necessarily narrow their relative development gap, complicating the selection of future development pathways. This study integrates forecasts of 43 indicators for 30 Chinese provinces based on 2014–2023 data, fixed-boundary TOPSIS recalculation, system dynamics, and NSGA-II multi-objective optimization to evaluate policy portfolios for 2024–2035. The optimization considers mean coupling coordination, mean absolute relative development gap, and standardized intervention intensity. Under business as usual (BAU), the coupling coordination degree rises from 0.6515 to 0.7396, while the relative gap widens from 0.0050 to 0.0707. Three independent optimization runs yield an approximate merged nondominated set of 411 portfolios. Compared with BAU, the comprehensive compromise portfolio increases mean coordination by 0.001853 (0.2627%) and reduces the mean gap by 0.001793 (4.0929%), with an intervention intensity of 0.2589. Compared with the balanced coordinated development scenario, it achieves nearly the same mean coordination with a 6.94% smaller mean gap and 53.57% lower intensity. Nevertheless, the gap continues to widen. Joint sensitivity tests show that coordination gains persist across the tested settings, whereas gap reductions depend on calibration. Rural broadband receives high allocations across tested policy menus, while grassroots management allocations vary more with menu and weighting assumptions. The findings demonstrate the value of jointly evaluating coordination, relative score balance, and adjustment requirements, with policy priorities conditional on the specified decision space.