Comment from audience: the average time to produce a textbook is ten years, and thousands of people touch it. The name on the book — the author — is a bit of a fiction. The name may remain same even as the product shifts under it.
This is true broadly in the modern marketplace. Taylor Swift is a singer-songwriter, but her songs are largely produced by a conglomerate of faceless employees. The seed of the song, the feel of the song is overseen and made coherent by her participation, but the songs are corporate productions in a way that Bob Dylan’s early works were not.
What’s true for a song produced over a month is much more true for a book produced over ten years.
When seen this way, the erosion of the author is in fact a bit of a lie too. See Buying Patterns and the Erosion of Authorship
Faculty may be caring less about authors and names. See Rising Support for Open Materials
Also remember that Historical Truth and Narrative Truth differ.