Here is Aaron Swartz on Wikipedia:
When you put it all together, the story becomes clear: an outsider makes one edit to add a chunk of information [to a Wikipedia entry], then insiders make several edits tweaking and reformatting it. In addition, insiders rack up thousands of edits doing things like changing the name of a category across the entire site — the kind of thing only insiders deeply care about. As a result, insiders account for the vast majority of the edits. But it’s the outsiders who provide nearly all of the content.
(Correcting Wikipedia’s founder, by the way.) When I visited my editor, Marian Lizzi, at Penguin, I realized that book publishing is exactly the same: Outsiders write the books, insiders edit them.
The curious thing about book publishing is similar to what Swartz noticed in a different realm: The content, the crucial stuff, is entirely from amateurs. No other industry, with the possible exception of craft shows, is like this. If I run a deli, I buy supplies and food from people who make their living selling supplies and food. If I make clothes, I buy my cloth from professional cloth makers. If I make cheese, my milk comes from professional farmers. Only book publishers endlessly deal with amateurs.
“When it comes to writing, we’re the professionals and it’s the book (and journal) editors who are amateurs.” Journal articles and trade books are different. In the case of journal articles, I sort of agree with you — we are professionals (because that’s basically what professors at research universities are paid to do — write journal articles). The journal editors are not amateurs — they make their living doing it — but they often have less experience than the authors. In the case of trade books, almost no one makes a living writing them. Whereas book editors do make a living doing their job. I guess it’s possible for a professor to have more trade-book experience than his or her editor, but it’s hard to imagine. Take Deborah Tannen. University professor, lots of trade books (five?). But surely she has a very experienced editor, commensurate with her great sales.