It's funny, since Stack Overflow has done EXACTLY this since day one (i.e. generate cash, with user knowledge provided for free).

The only difference is SO uses community, gamification & reputation facades, to convince users to participate for free.

With OpenAI its simply a blackbox, no credit is given.

So I guess the lesson is people are willing to participate and share things for free, as long as they're given credit, community standing or something along those lines.