I'm pretty sure OpenAI pays them even fatter salaries. I worked for a nonprofit at one point. People think that nonprofit automaticall means a pay cut, but they paid me about as much as Google did before, except it was all-cash. From the fiscal standpoint nonprofit merely means that all the revenues and donations get spent on programs and salaries, not that it pays a pittance. Organizationally, there are some interesting features to it, though: no stock, no owner, limits on control, etc. But financially nonprofits can pay very well indeed.