Yeah, that's been a problem for years now. They keep announcing movies when no work has actually been done on them, and nobody has any idea if/when they'll be coming out. Just looking at
the "Other projects in development" section on Wikipedia, it's an insanely long list where they seem to announce a project as soon as it has a single screenwriter attached, even if there aren't any actors cast, directors chosen, etc.
I really hope that we get a Green Lantern Corps movie and a Man of Steel sequel, though. Henry Cavill finally felt like a traditional Superman by the end of Justice League, in my opinion, and it would be a shame if he was recast.