Biggest Software Company - Slowest to Patch

CNN is reporting that Microsoft hopes to have a patch for the severe security flaw discovered last week, by next week. I know that lots of people have wondered aloud about this before, but why is it that MS, the largest software company in the world, takes so darn long to come out with security patches. Sure they put out more security patches than anybody else, which means each patch has to wait for the previously ordered patches to be written. Still, shouldn't they be willing to put other patches on hold when a gaping hole like this one is found? I don't know... thank God for my Mac.