There are conflicting rumors that the Dark Sword has either been cancelled or is being developed into another project, so it's safe to say that, at this point, nobody really knows what is going on.
Well, before the photo of the mock-up, I would agree with you completely.
With the reappearance of the Dark Sword mock-up, which looks almost identical to the concept shown 12 years ago, it is almost certain that they have been working on the exact same design all these years. Thus, the original program has not canceled or changed.
Whatever those old rumors were, they were most likely baseless guesses. All of them were made because there was no information on it. Now with the appearance of the mock-up, everything is changed. None of the old rumors mean anything any more.
At this point, in my opinion, we have a pretty good idea as to what’s going on. The Dark Sword concept was picked up by the PLA and worked on in secrecy until they became confident enough to let the world know.
My rationale? The current mock-up is almost exactly the same as the original concept. This would have not happened if the original project was canceled or changed in any way. No one would keep a flawed design when it is bad enough to be canceled or changed.