Fans who follow more closely can correct me if I'm wrong, but....
The author streams and does events, but hasn't given any updates in a long time. He did a fund raiser where a goal was releasing the first chapter of his next book, which he supposedly has been working on since 2011, and he never did despite meeting the goal. Sure feels like despite supposedly working on it for 2011 he hasn't even made a draft of the opening chapter.
Additionally, his previous editors and publisher have said they haven't seen any indication he is working on them at all. So it doesn't seem like he's agonizing over revision 512 and still not happy with it. Seems like he just never made a first draft.