Yeah, but that exploit was developed and practiced for weeks or months ahead of time.
The Pwn2Own contents are nothing but crap marketing hype shows for the journalists. They mean NOTHING in the real world. If they did, you'd see OS-X viruses running around in the wild. There are none.
But your statement about Win7 being the most-malware-resistant OS from Microsoft is right on.
Impressive, it still allows itself to be exploited. Before you go all wrrrrrrgbbbblllllllllL!, it is a fine OS for casual use and gaming; I'm looking from more the business aspect as to why it's a pain.
Don't get me wrong, my quasi-vaunted linux kernel is sucking wind this past month...Two very nasty exploits that cost me outages for reboots after patching; grrrrrrrrrrr...(don't tell me about ksplice; I can break it with a simple loop in a shell)