GraphQL is touted as a technology which saves developer time by avoiding the need to develop REST APIs, and instead just expose your database to the world and let your frontend just get whatever data it needs.
No wonder you're seeing small teams using it. It's not because of FANG, not because of cargo cult development, not because of incompetente. It's because small front-end teams don't spend their scarce resources on areas where return of investment is limited.