That's the real distinction: does the for-profit subsidiary subsume the supposed public good of the parent non-profit?

If OpenAI Co. is gatekeeping access to the fruits of OpenAI's labors, what good is OpenAI providing?

Anyway, to answer your question, no, not okay to close up the nonprofit and go 100% for-profit in that case.

Concisely, in any human matteres: Do what you say you'll do, or, add qualifiers/don't say it.

Take funds from a subset of users who need support services or patch guarantees of some kind, use that to pay people to continue to maintain and improve the product.

They had one of the best browsers in the world at one point.

Their sell-out path was hundreds of millions of dollars from GOOG to make their search engine the default, and, unspoken: allow FF to become an ugly, insecure, red-headed stepchild when compared to Chrome.

Likely part of what took priority away from Thunderbird, at the time, too.