Could be that the other key factors like traffic and incoming links are astronomical, so Google's content dupe penalty is out weighed.
It's a case of "doing it better" and not necessarily doing it the first time. While they may be scraping content and it's all duped - they simply must get the huge traffic numbers and incoming links because it's content all in the one place.
I'm just assuming of course - without doing an audit who knows - but must be frustrating for you if you are working on a campaign against them.