>Some books are never published in print at all and exist only as ebooks and/or audiobooks. And many books exist in “print on demand” form in which a physical copy doesn’t exist until someone purchases it. In the old days, books would go out of print when people stopped buying them. But in the modern digital age books can exist “in print” for forever.

Yeah that was the answer to my first question. If they're only selling a few copies, no need to print many / any.