The readers have since then "grown up", quite literally as well. To expect the same kind of frenzy around Potter books now would be nothing short of foolishness. I am a huge Potter fan and have read and reread every single page of every single Potter novel numerous times. I believe the Harry Potter series has reached a logical conclusion and no one should tamper with it any more. It has been a magical journey and a near perfect one. Lets us not spoil the magic. Releasing another Potter novel after such a conclusive Deathly Hallows would be disastrous, especially for us fans. I hope the J. K. Rowling realises that.