To Compete or Expand? Offline Retailer’s Social Commerce Entry via the Platform Under Consumer Heterogeneity
构建博弈模型研究线下零售商通过社交电商平台扩张渠道的影响，发现高佣金可协调市场并提升双方利润，但社交推荐可能损害零售商整体盈利，且渠道扩张可能因提价而降低消费者剩余。
Social commerce is disrupting traditional offline retail, yet it also offers opportunities to reach broader consumer segments, thus facilitating new growth. This study develops a game-theoretic model featuring an offline retailer, a social commerce platform, and a market segmented into multichannel comparison (MC) and social-commerce-preferring (SP) consumers. To investigate the impacts of the retailer expanding into social commerce specifically to access SP consumers, we compare two scenarios: scenario C, where the retailer operates offline and competes with the platform, and scenario H, where the retailer expands into the social commerce channel via the platform, which acts as both a competitor and an agent. Our findings reveal that the platform commission, traditionally viewed as a retailer cost, can function as a market coordination mechanism, where a high commission can surprisingly increase the profits of both the retailer and the platform by softening price competition. Furthermore, although a more competitive market is not conducive to the profitability of the two entities, it can lower the commission threshold required for both entities to prefer channel expansion. Critically, while social recommendation boosts the social channel's profit, the resulting cannibalization of the offline channel can be so severe that it ultimately harms the retailer's overall profitability. Finally, we uncover a welfare paradox: while channel expansion offers consumers more choice and social recommendation brings positive utility to MC consumers, the resulting price increase may ultimately harm their surplus, suggesting that the competitive scenario is sometimes more beneficial for consumers.