Earlier quoted context omitted.
Market share: Windows 90%, Mac 9%, Linux 1%. Where are virus writers going to put most of their effort? Windows being as secure as Mac wouldn't help make it safer because a lot more implemented exploits are going to exist in the wild.
I, for one, am pretty bored by the market share defense. There are millions of macs out there, owned by people who could drop a little coin on their hardware, and that make them less of a target? There's not one virus writer out there who doesn't want the cred and the potential gain of a new audience of victims, many of whom are probably pretty complacent about security because they've never had to worry about it? Th…
This is why homogeneity is dangerous. The more diversity an ecosystem has, the less vulnerable it is to viri, whether we're talking about crops or computer networks.