The edge case is actually quite common-- many authors mostly survive off their entire body of work, not just the works published recently. This was an issue in e.g. Disney, who refused to pay royalties to Star Wars books published many many years ago because they claimed to have purchased assets but not liabilities. One of the authors who was suing for royalties needed the money for cancer treatments. Bad look.
5k/work is not cheap. That's how much publishers may pay for a book. 15k/work is prohibitively expensive for books.