The most recent trends in the electronic commerce research have suggested that forming an ecosystem around a platform would create a winning solution. The ecosystem, consisting of vendors and external actors, would create competitive advantage for the platform owner. Furthermore, the sheer number of the actors has been used as the measure of the ecosystem’s well-being against competing ecosystems. Whereas a number of studies has been devoted to analyse the well-being indicators or structures of software ecosystems and the importance of complementors and complements are acknowledged, there is lack of studies addressing how the complementors affect into the evolution of ecosystems. This conceptual analysis aims to open discussion on this topic by using the mobile application ecosystems—such as Google Play or Apple’s iOS—as the case subject. While the results suggest some implications for the platform owners and complementors, more work is needed.