So recently author Lynn Shepard posted a blog saying JK Rowling should stop writing after publishing The Casual Vacancy. At first I was ready to see things from her perspective because of the heavy criticism the book has received. Many have called the book "mediocre at best" and a lot of people have openly wished that she would go back to Potter and Potter-esque books. I've heard some theorize that the book would have been better if she'd "let go" of the Potter world and stop trying to add to the world afterwards, as it would have allowed her to really devote herself more to what she's currently writing. Part of this is fueled by the fact that TCV seems to try to be as un-Harry Potter as it can be at times, which could be argued is JKR still allowing her Potter world to exercise its hold on her. I'm listing all of this because this is what I was expecting from the article: for Shepard to say that she wanted JKR to stop writing until she can figure out what she wants to do as an author. Sort of the whole "find yourself and then write" type of article.
No, as you can guess this is not the type of article that Shepard wrote.
The article is pretty much just Shepard asking Rowling (and arguably by extension, all major league writers, thereafter referred to as MLW) to stop putting out books because it makes it harder for smaller authors to get sales and attention. There are so many things wrong with that concept that I couldn't help but think of that John Cleese gif:
Now the thing is, Shepard isn't entirely off base with that remark. A lot of publishers will choose to ignore new, small, unknown, and/or independent authors because they want to stick with their known commodity. And an author is very much a commodity. The average publisher sinks a lot of money into even the smaller authors, so they stand a lot to lose even if the author is e-book only.
However the idea that a publisher would automatically pick up various other authors if a MLW stopped writing is a very faulty one. They might look for something to fill the gap, but odds are they'll just lean a little harder on the other authors they already have in their stable.
(Any excuse for a Futurama picture, right?)
The reality is that while publishers do want to stay with the "tried and true", the existence of MLW in any given genre makes it more likely that a publisher will want to publish similar works by various other authors. This doesn't mean that the publisher is going to pick up every author or even your work, but it does make sense. After the urban fantasy market boomed years ago with the output of various MLW in the field, multiple publishers rushed out to snap up every Sookie and Anita clone they could find. You can also see this in the cozy mystery genre with just about anything involving recipes or the supernatural. The lack of a MLW in the field that consistently brings in money will just make the publishers assume that the genre is "tapped out" and will likely stop looking to sign new authors while cutting a few other authors loose from their contracts.
Now if you're talking about how the media covers authors, then sure- there are a few arguments someone could make about that as well. Some outlets just don't want to cover too many of the same types of authors at a time unless they're doing a compilation piece about various authors in a specific genre and/or that are similar to a MLW. They don't want to be boring or lose the idea that they're about all things entertainment or news, so they try to mix things up. However a lot of those places tend to be fairly major, so we could also apply the arguments above: there's no guarantee that they'll decide to write about other authors in the genre for the same reasons publishers won't look for new authors.
This is also overlooking the obvious: if JKR really loved writing then why should she stop? As a coworker of mine said upon hearing about the story, "Wouldn't someone who really loved writing want to keep writing? Why would they stop?"
Ultimately a MLW deciding to bow out of writing entirely wouldn't have any true positive effects on the world of writing as a whole. It's not like it's a position at a business where the office manager or company president steps down and there has to be someone there to fill his or her shoes. Sure there might be something new that someone could find, but lets look at it this way: JKR hasn't written a new Potter-type book in a long while... yet you don't really see a huge and overwhelming flurry of people getting published. People like to say that Twilight was the replacement Harry Potter, but the thing is... Twilight was published in 2005 and was already wildly popular by the time the HP series ended in 2007. Meyer may have gained a few spillover readers after the HP series ended, but odds are that a lot of the people who were reading HP probably picked up Twilight because they'd enjoyed the whole reading experience with JKR and wanted more.
In the end, that's why MLW can be so beneficial: they make it more likely that someone will read something and want to read something similar to it, thus enabling them to find your book. Sure, JKR and SM aren't really similar in ways other than both are supernatural but the work did come up in a lot of "if you like... " searches. Trust me- my Amazon feed was filled with recommendations for various authors, both independent and well known. Having MLW in the field only heightens the chances someone will find your book.
And as for someone else going into another genre... the same rules apply. If a MLW publishes in your field, regardless of how good the book is, odds are high that it'll bring new readers in. They might hate the MLW's book, but then they might think "I liked the idea of this, so let's check out something else to see if there's anything better out there". Some might toss the MLW's book aside and never read anything from that genre again, but then those readers were unlikely to have picked your book up anyway... so you're not really losing a reader.
Plus think of it this way: there will always be a bigger writer than you. While you're praying that ____ stops writing, someone else may be wishing that you'd stop writing so they could have "your job" as an author. By this definition everyone published by a major league publishing house should stop publishing after one book so the next one can have their turn. Needless to say, I don't think anyone wants to actually do that.
*If JK Rowling Cares About Writing, She Should Stop Doing It