George Miller Talks on Why “Justice League: Mortal” Never Happened

George Miller, the once director of the almost in-production Justice League: Mortal, who was also rumored to be directing Man of Steel 2, which has since been debunked by him, recently spoke with The Hollywood Reporter on the never made Justice League film, after being asked on both Man of Steel 2 and Justice League: Mortal.
One thing to note and maybe not read too much into, is that Miller never answers the Man of Steel 2 question and does state Justice League: Mortal was the main one of the two he was going to direct. interesting wording is all.

You were going to direct a couple of them: Man of Steel 2, Justice League. What happened?

Justice League was the main one. That was, oh, seven years ago, I think. And there was a really great script. And Warners said, “Let’s do it. Let’s do a Justice League.” I really was attracted to it. But there was a writers strike looming. We had to cast it very quickly, which we did with Warner’s casting people. And we cast it really quickly and we mounted it very quickly. And it depended on a start date and it depended on some basic rebate legislation that had just got through a new Australian government. But it was just too big a decision for them to make in the time. And that fell through and the whole film fell through. We almost got there. And it wasn’t to be. But that happens a lot, where films line up and the stars look like they’re aligning and they didn’t.

Source: HollywoodReporter.com