Well, we'll see
The issue, I think, will be how many authors with her kind of pull don't have their own ebook rights. If people like King, Grisham etc. are locked into publisher contracts, then whatever Rowling does will be a one-shot deal. And new authors who might go 'wait a minute, didn't Rowling kick butt on her own?' may find that the new contracts publishers expect them to sign do not offer the no e-rights loophole that Rowling is exploiting...