Originally Posted by Spade
A decent explanation for why all the Krypton colonies are dead could be Brainiac "collecting" their culture. But that would make this another alien invasion story, and we've been there before to the chagrin of some. I'd rather it was Luthor, with the dumb "I want land" motivation dropped in favor of that ruthless businessman John Byrne wrote in the Post-Crisis story.
I thought they explained why those colonies were all dead in Man of Steel. I thought it was just that the Kryptonian council made it illegal to leave Krypton and they just ran out of supplies.