GraphQL over websockets doesn't seem to be widely used yet. There are several libraries, articles and docs available but half of them don't work, require additional new technologies or provide non-standard solutions. I tried to find a simple, reliable and scalable solution that didn't need much more knowledge outside of Apollo, GraphQL and WebSockets. I also don't want it to rely on unrelated libraries like Express so I don't lock myself in. It will probably also benefit the server structure to keep Apollo separate from other modules (sort of like a microservice).
apollo-server (while not very performant) seems to be one of the few proven technologies for having a GraphQL backend in Node.js. Using that on the server is probably going to provide the quickest road to production, as it's widely used it will probably have decent documentation and issues can probably be solved by a few Google queries. I