True, but its not pure OpenAI GPT. If the point is dogfooding, then they'd use Copilot instead of using OpenAI's models directly
They do.
They had phi for a while. Interesting that they haven't really continued with anything like that.
Phi was more of a research project. Not trained on real world data but synthetic input. That's really good to control if you go for strict limits but it also loses a lot of originality.