I'm not sure hackers brought their "A" game to this event. In contrast to earlier events, winners must disclose their methods to participate in return for only $150,000 per exploit. A black hat hacker could make much more from their methods, and a white hat hacker could as well--in consulting fees.
You're thinking of Pwn2Own. Pwnium has always required disclosure, while Pwn2Own only required full disclosure for the first time this year.
And $150,000 is actually getting quite close to what you could make for an exploit of a browser on the black market, especially with all those Java and Flash plugins still running all over the world, depressing exploit prices as long as they're available.
