In the after-sales service market, understanding both the internal degradation of products and the external incentives within warranty period is crucial. Efforts into preventive maintenance can slow down the internal degradation, but these efforts are also influenced by external strategic services. Enabling an Industrial Internet of Things (IIoT) platform for preventive maintenance requires carefully considering the benefits instead of merely increasing efforts. This paper addresses these complexities by first proposing an additive degradation model to characterize the internal deterioration of products and the impact of efforts into preventive maintenance. It then introduces a sequential game model based on the IIoT platform, examining interactions between manufacturers and cooperative competitors under three competitive schemes: traditional competition, monopolistic competition, and shared competition. Equilibrium prices for new products and after-sales services are used to analyze external incentives. Utilizing these equilibrium prices, the paper derives profit and reliability functions of manufacturers and cooperative competitors under each competition scheme. Finally, this study combines the efforts into preventive maintenance and the internal degradation mechanism of products through equilibrium reliability functions.