Technically, the main problem with attacks is the end user.  Regardless of how "safe" the operating system is, if the end user is dumb, it'll get hacked.
So, I never run anti-virus on my Windows, never ever update or patch it, and have never had any problems with viruses etc.  That's primarily because I know what I'm doing.

Viruses don't just appear, the user has to actually install them (regardless of whether they're aware of it).


Anyways, now that Macs run on PC hardware, MacOS has been hacked to run on PC, and Windows/Linux will run on Macs too :P