Today I heard someone praising Linux as a desktop OS, on the grounds that it's not very susceptible to viruses. This, he said, was good because it “saves cycles” and cuts down on reinstalls.
Not because they're a security threat. That, apparently, was not on the radar.
I think the cycles he was talking about were those taken by antivirus software, not by the viruses themselves, but the point is clear: many users see viruses as an annoyance, not a threat. Performance and convenience — those are the things that matter.
The speaker was a programmer who is involved in designing network protocols. Maybe he was only giving the reasons he thought his audience would understand. I didn't ask; I'm afraid of what the answer would be.