Authors are, with few exceptions, worthless scum. But, knowing that, even I was flaggergasted recently when I picked up a collection of stories by Chekhov, with an introduction by Richard Ford, and found the book had a biography of Ford... but not of Chekhov.
One of the few exceptions to the rule of authorial narcissism is the Icelandic novelist and poet Sjon, who, as editor of the Nordic writing anthology Dark Blue Winter Overcoat, didn't include any of his own work.
A few years ago I read a personal essay by the author of a popular book in the “misery memoir” genre. In the essay, the author described their lowest moment as being when they were jogging past a McDonald's and saw the employees watching and laughing. The author was horrified that “even” people working at McDonald's felt able to mock them. If only those proles knew who they were laughing at!
This kind of grandiosity is, in my experience, more common among authors than not. I've long suspected that the reason authors are so self-important is that we know how unimportant our work really is.
If there's anything positive about the pandemic, it's that it brings home whose work really matters. You can't eat books.