The GraphQL ecosystem has grown amazingly quickly over the last year. It's definitely not a single-vendor technology at this point. Check out this list of GraphQL libraries, tools, and implementations:
https://github.com/chentsulin/awesome-graphql
The majority of people who are using GraphQL are using an implementation from someone other than Facebook (on either the client or the server, or in many cases both).
(And for what it's worth, I did see a "Why not RDF" slide in one of Lee Byron's decks, and those of us at Meteor who are working on GraphQL are definitely aware of the RDF/SparQL roots. I think what's driving GraphQL's growth is, first, it addresses a very timely problem - fetching all of the data for a screen in a mobile app in a single round trip without coupling your backend to your UI - and second, the focus on tooling and developer experience which has been a weakness for SparQL.)
The majority of people who are using GraphQL are using an implementation from someone other than Facebook (on either the client or the server, or in many cases both).
(And for what it's worth, I did see a "Why not RDF" slide in one of Lee Byron's decks, and those of us at Meteor who are working on GraphQL are definitely aware of the RDF/SparQL roots. I think what's driving GraphQL's growth is, first, it addresses a very timely problem - fetching all of the data for a screen in a mobile app in a single round trip without coupling your backend to your UI - and second, the focus on tooling and developer experience which has been a weakness for SparQL.)