Comment by druskacik

He wanted to be the CEO and merge it with Tesla[0], but the researchers had a problem with him (some had a problem with Altman as well, but that's another story). He did not have any real options since OpenAI was a non-profit then, so he just left. The new book The Optimist[1] about Sam Altman has some more details on this and other OpenAI Game of Thrones, I definitely recommend for those interested.

[0] https://openai.com/index/openai-elon-musk/

[1] https://www.goodreads.com/book/show/223400731-the-optimist