David Aucsmith, head of technology for Microsoft stated that hackers are lazy and instead of finding exploits themselves, are instead waiting for patches being released and then hacking them.
Windows is known for having persistent problems regarding malicious hackers, and have a reputation for security problems.
David Aucsmith compared these problems to the recent vunerabilities discovered by Eeye Digital Security. No exploits were produced until there days after the patch was made available. Source