I am also not really getting the argument. If I as a human want to learn a subject from a book I buy it ( or I go to a library who paid for it). If it’s similar to how humans learn, it should cost equally much.
The issue is of course that it’s not at all similar to how humans learn. It needs VASTLY more data to produce something even remotely sensible. Develop AI that’s truly transformative, by making it as efficient as humans are in learning, and the cost of paying for copyright will be negligible.