>And Altman's Wikipedia page says he is a funder of the company.

Funder, not founder, yes.

If OpenAI themselves chose to distinguish between founder and co-chair, then I really dunno what else to tell ya.

You're confused by the fact that OpenAI is a charity.

There are no shareholders of a charity, instead the board are the notional owners and take decisions that shareholders would.

So in this context Musk is founding board member and thus a founder as it would apply to a for profit entity.

As I said you are misinterpreting the page. We know this because according to your interpretation Elon Musk is not a founder, which we know is false. They probably didn't want to repeat people's names, so they mentioned it where it is most relevant. If you still have any doubts ask ChatGPT. I asked multiple ways, and it says he is a founder.