I wondered that too. A subtle endorsement of Sama perhaps. A way of saying there's no bad blood there despite what the press was saying about his 'firing' from YC. Sama did a great job running YC, and certainly made PG a boatload of money. Also seeing the success at OpenAi, hard to argue Sama didn't make the right call to leave and focus on it, could hardly have done that plus keep running YC. (my guess at what happened is Sama started openai on the side and gradually it became more and more of his focus until there was a conversation about whether he should focus exclusively on it, which they mutually decided should happen).