In Back Issue #12, John Byrne revealed:
"The reason this [project] didn’t happen was that going in, I said I want this to be a separate universe. I want this to be not connected with the DC Universe in any way. And DC said, yep, fine, that’ll be great, that’ll be good. And then I had actually done the cover and the first two pages of the first issue and they said, “Oh, by the way, Cap has to be in the Justice League.” And I said no, we agreed. And they said he has to be, it’s absolutely necessary. I said, well, bye then. It was another one of those cases where I made my unreasonable demands loud and clear, up front, they agreed to them, and then said, “Oh, no, we’re changing our minds.”
A few more recent renditions of Captain Marvel by Byrne.