It could be done without sharing advances, earnings, sales figures. The focus would have to be different: on the process, rather than the product. It might help show people how trade publishers DO market and promote the books they publish, for example. Just a thought.
Something like that would be great. I used to see posters in the Tenth Circle thread sharing this kind of info about their published or soon-to-be-published books, and it was hugely helpful as I prepared to go through the process. But it's been dead there for a while. Maybe people don't realize it's there, or don't expect to find that thread in Rejection & Dejection? (It makes sense in that "sub hell" is a place to which most writers have to return over and over, published or not. But the thread wasn't just about being on sub.)