Well if the author/ copyright holder stops publishing the book and no one else is allowed to it is going to quickly fade into irrelevance, even though there are

Well if the author/ copyright holder stops publishing the book and no one else is allowed to it is going to quickly fade into irrelevance, even though there are a few copies out there being kept safe indefinitely. Whereas if the book is in the public domain, the quality of the book and popularity will decide whether it continues to be read, rather than anything artificial.