Yeah, the WebKit exploit will work effectively unmodified on Safari. And the sandbox escape used against Chrome on Windows was a kernel bug in surface that can't be turned of from user-space (or really at all on Win7). Also, they softened the target quite a bit by using 32-bit Win7 for the contest, rather than 64-bit Win8 (or even 64-bit Win7).

As for why no one's targeting Safari, I think it's simple market forces at play. The iOS exploit market is established and pays very well, while the core vulnerabilities, expertise, and techniques are all shared with Safari on Mac OSX. And since Safari isn't a soft target (in no small part due to Abhishek's mass slaughter of WebKit security bugs and our bounty program), $65k just doesn't compete with the real-world exploit market.