The main role of a product manager in tech companies involves overseeing the development and success of a product throughout its lifecycle. This includes conducting market research, defining product vision, and coordinating cross-functional teams such as engineering, marketing, and sales to ensure alignment with business objectives. Product managers also gather user feedback to inform improvements and updates. They act as a bridge between stakeholders and development teams, ensuring the final product meets user needs and market demands, ultimately contributing to the organization's overall strategy.