I didn't miss it, I just don't buy it. Lots of people create and write in their free time, without any financial incentives whatsoever.
I'm okay with writing books for profit, though. But if your business case depends on artificially limiting what users can do with their copies, then your business is fundamentally unethical, whether it's a one-man company or OpenAI. It's not a bad thing for such a business to go under.
Yes. It is good (and IMO should be encouraged) that derivative works can are made, even if it would make you less money.