Yeah, I assume the low usage of GraphQL in this survey coordinates/correlates with the low usage/knowledge about Apollo in this survey. Apollo seems the most invested in ramping up strong tools for GraphQL, so of course developers aren't likely to be using GraphQL if they haven't yet heard about/explored Apollo's efforts.
For instance, apollo-link-rest would be a strong way to bootstrap into GraphQL for shops with heavy REST investments.
That said, Apollo aren't yet doing themselves favors with nearly every part of their tooling still showing a "Caution: Active Development" warning. That keeps them right on that cusp of "Should I use this in production?" worry for enterprise, and slows adoption probably more than they intend.