With the increasing importance of ecosystem in a business environment, the value of open innovation is receiving great attention. Under open innovation, companies open their knowledge, capital, and other resources to cooperating companies; on the other hand, under closed innovation companies depend solely on their own resources. In this paper, we compare closed and open innovation using the simulation method, and confirm that in terms of total capital and production of the industry, open innovation provides greater opportunities to the entire ecosystem. Moreover, Schumpeterian competition, which is a dynamic of closed innovation, functions even under open innovation. Our findings highlight that not only small but also large companies can receive the benefit of an enlarged industry under open innovation