It’s possible that it’s a matter of resource allocation – with the studio wanting to put more focus on some projects more than others (namely projects not named “The New Gods” or “The Trench.”
That’s the million dollar question, and there doesn’t seem to be an official answer.
The statement from Warner Bros. announcing the projects cancellation doesn’t say anything that even resembles an explanation, and even suggests that it isn’t totally dead, but instead just dead for now (“The projects will remain in their skillful hands if they were to move forward in the future.”)