At this point, I don't think it's still Jim; not any of it since "The End" tweet. It's the publisher. Jim (or Prescielle, or other "insider" sorts) are giving info when/as they get it, as they are allowed to release it. But the publisher is in the drjvers' seat at this point, and the next book is coming out when they decide; just info about the release is coming out when they decide.
I saw some suggestions that maybe Penguin is trying to fit the release into their schedule so that this doesn't cannibalize other lines' sales, nor those lines cannibalize PT. They may have quarterly revenues they want to balance. There may be a prior commitment by Marsters, in conflict with recording the audiobook, and they're trying to coordinate that. Etc etc etc.
Agreed. I tried to think about the release from a money making point of view, though I admit, I don't really have a clue, just what I think.
October would have been good for selling.
In January people still read their Christmas books (maybe even bring them back to the stores, if they are not interested in reading them) and maybe won't look out for new ones, except us fans, but there may be new readers/buyers that go into bookstores or browse through the internet in search of new stories. I wouldn't do that in January, because I would have to wait for my finances to recover. That would happen in February at the earliest point. There is nothing else in February. Most people will have read their December books and be ready to buy new ones.
So I think, we might have to wait at least until February. And maybe longer, if it is true that they wait for the audio release.