Symbiotic relationship of prefabricated building supply partners under different government incentive policies

Purpose This study examines the co-evolutionary behavior of contractors and component suppliers in prefabricated building (PB) supply chains under bounded rationality and different government incentive policies. It aims to clarify how asymmetric incentive allocation and contractor–supplier interactions shape symbiotic outcomes and to provide a theoretical basis for the coordinated promotion of PB. Design/methodology/approach By integrating symbiosis theory with game payoff matrices, an asymmetric independent symbiosis density-game model was constructed between contractors and component suppliers. By analyzing the model's stability conditions and employing system dynamics simulations, this study examines the decision-making dynamics and evolutionary trajectories of contractors and component suppliers under different government incentive policies. Findings The results indicate that the model exhibits distinct, stable equilibria under different initial conditions, with stability conditions closely tied to the government's incentive allocation and the behavioral choices of game participants. Greater supply chain interconnectedness effectively promotes co-adoption of PB. Moderate increases and appropriate incentive allocation, coupled with greater supply chain interconnectedness, facilitate the adoption and development of prefabricated construction. Originality/value This study extends density-game modeling to contractor–component supplier relationships in PB supply chains by incorporating asymmetric carrying capacities, incentive allocation, and cross-party interaction effects. Unlike conventional evolutionary game models that focus on discrete strategy choices, the proposed framework captures the continuous evolution of participation scale under capacity constraints and identifies unilateral adoption, co-adoption, and path-dependent outcomes. Coupling analytical stability analysis with system dynamics simulation further links equilibrium conditions to evolutionary trajectories.