Meta released their OPT model which they claim is comparable to the GPT-3 model. Guidance for running that model [1] suggests a LOT of memory - at least 350GB of gpu memory which is roughly 4 A1000s, which are pricy.
Running this on AWS with the above suggestion would cost $25/hr - just for one model running. That’s almost $0.50 a minute. If you imagine it takes a few seconds to run the model for one request… easily you’ll hit $0.05 per request once you factor in the rest of the infra (storage, CDN, etc) and the engineering cost, and the research cost, and the fact that they probably have a scale to hundreds of instances for heavy traffic and that may mean less efficient purchased servers.
OpenAI has a sweetheart deal with Azure, but this is roughly the cost structure for serving requests. And this doesn’t include the upfront cost of training.