There are two ways to look at [the results]. It's possible that the malware kept coming, and Apple either failed to notice it, or just gave up trying to keep up. If that were true, though, we'd expect to still be hearing about it, both in the general press and from TUAW's contacts throughout the Mac ecosystem of developers and support staff. But we've heard nothing.
The other option, then, is that the malware has stopped evolving. The MacDefender authors gave up trying to issue new variants, and nobody else has (so far) taken their place. The Mac malware scene is... well, if not dead, then asleep. Stunned. Pining for the fjords.
A very smart take on the impending doom that Mac users were sure to face only a few months ago. Kudos to Mr. Gaywood for taking the time to bring this information to the public.