Based on the prices the Apollo dev was slinging around, I highly doubt Relay will be around even after this guy "figures out" what to charge his users. Unless he's aiming for whales with deep pockets I give it maybe 3-6 months before he also folds. Reddit can also easily move the goal post on Relay, which is inevitable, because Reddit wants people to use thier app.
This is what I'm thinking too. Narwhal is sticking around but once Narwhal 2 comes out it'll be $5-7 per month and more for a user who makes a lot of API calls. If I'm remembering correctly Christian figured it would be close to $10 per month to support Apollo's heavy users without going in the red. That's crazy money to pay for access to Reddit.