Cartoonist Kayfabe interviewed Rob Liefeld and the conversation turned to Alan Moore and how Alan tried to offer a different Moore to write the third season of Supreme. That part of the conversation starts around 1:16:00.
Basically, Liefeld says that Alan wanted to keep making $10,000 an issue, but to be co-writing with Steve Moore. Liefeld refused and that was the end of Supreme. Liefeld doesn't mention that Alan was hip deep in ABC by this point and Liefeld initiated this conversation.