What is the fine-grained topic of the following text: Departing from the conventional wisdom, Gans identifies two kinds of disruption: demand-side, when successful firms focus on their main customers and underestimate market entrants with innovations that target niche demands; and supply-side, when firms focused on developing existing competencies become incapable of developing new ones. Only return the topic.
Types of Business Disruptions: Demand-Side and Supply-Side