Windows users normally load up their computers with antivirus and anti-spyware programs. As a result, the typical PC is like the Great Wall of China. On the other hand, you have arrogant Mac users who believe they’re invincible and don’t bother to protect themselves. Virus writers eventually start taking note of this and focus their efforts on Macs.
There is some truth behind that belief. It has now been ten years since the release of Mac OSX and the number of self-replicating, self-transmitting, self-installing viruses in the wild is STILL ZERO! There are only seventeen known Trojan horse programs in four families, and the OS itself will warn you if you attempt to download or install one of them or a variant from one of the known families. There is no spyware.
The virus writers MAY be turning their attention to the Mac, but they are finding that writing malware for the Mac is at least an order of magnitude more difficult than writing for Windows. THEN, your hypothetical malware writer has to find a viable vector to spread his hypothetical Mac virus. So far the only one that works at all is social engineeringpersuade the user to download and install itI.e., a Trojan. Every other attempt has failed, miserably.