If everyone used Linux, guess what, the problem would be just as big as it is now with windows users. If you were wanting to target an audience, would you set your goals on New York City, or Belton, Texas? Linux is great I use several different flavors, but as far as software goes, there are limits, so I use windows far more often, most people do and therefore the target audience. And since Linux is basically open source, well some enthusiastic scammer/hacker/script kiddie could develop his own open source vulnerability virus/trojan/malware of some sort, then what do you do? No anti-virus company is going to touch that, no profit in it,...one problem on Linux possibly affecting a handful of PCs. All this highly unlikely, but you catch my drift.