Edit: nvm I missed the point was about firing the board.
Pedantic, but: LLCs have "members", not "shareholders". They are similar, but not identical relations (just as LLC members are similar to, but different from, the partners in an partnership.)
That's functionally true, but more complicated. The for profit "OpenAI Global LLC" that you buy ChatGPT subscriptions and API access from and in which Microsoft has a large direct investment is majority-owned by a holding company. That holding company is itself majority owned by the nonprofit, but has some other equity owners. A different entity (OpenAI GP LLC) that is wholly owned by the nonprofit controls the holding company on behalf of the nonprofit and does the same thing for the for-profit LLC on behalf of the nonprofit (this LLC seems to me to be the oddest part of the arrangement, but I am assuming that there is some purpose in nonprofit or corporate liability law that having it in this role serves.)
https://openai.com/our-structure and particularly https://images.openai.com/blob/f3e12a69-e4a7-4fe2-a4a5-c63b6...