From a recent podcast [0] it seems unlikely that they make profit from gpt-3.5-turbo, at least not in the sense that it pays for employee salaries. Instead, from the conversation, it seems like OpenAI is aiming to make money mostly from enterprise partnerships, probably to fine tune GPT-4 or what not to your own private data.
I think this makes sense, you keep competitors at bay by offering a good-enough, dirt-cheap API and then ask the big bucks for the private setup. This mirrors Stability AI's strategy, which is basically that but with open source models.
[0] https://open.spotify.com/episode/2v8Sa1RNnfZa6l7JIYmIL2?si=o...