JK Rowling opens her own site, Pottermore, for gaming (of some sort), audiobooks, and ebooks.
Probably smart. Somebody of her unique stature doesn't need to deal with Apple's and Amazon's bureaucracy, nor to pay their 30%. They don't add anything to justify that, she brings the customers now, not the other way around.
BTW, there are also authors of far, far lesser stature who say that they earn much more by *not* selling on amazon, due to Amazon's habitual discounts eating up the author's profits.