12 Biggest Unanswered DC Movie Mysteries

When Zod unveils his plan to terraform Earth, he mentions to Clark Kent that he and his underlings visited other Kryptonian colonies where "all they found was death". Despite that, he's able to recover a World Engine (so presumably the colonists had the ability to terraform other planets and didn't just die out from environmental discord (unless they were idiots), and the random scout ship sent to earth had a Genesis Chamber, so you could assume others did too.

So why did a race of people famed for their technological advancement succumb so easily? You could presumably account for some of them with disasters or hostile locals, but all of them? That's got to be unlikely. Maybe their inability to thrive suggests evolution didn't want them to survive?

Either way, it's an almighty head-scratcher that is just sort of glossed over, despite how confusing it is that Krypton would simply stop its space programme and cut off all external communication to the colonies and let them wither and die. So much for an advanced society.