I'm not vulnerable to computer viruses. I haven't had a single one in well over 30 years of computing, and I've never used antivirus software. It's too big a drain on resources. And yes, I do have measures in place in case a virus ever appears: wipe the drives, reload, and continue. Simple.

This is absolute fact. You can avoid almost all viruses by following proper safe computing practices. Companies get viruses because of individual stupidity.

I believe the viruses are written by the antivirus companies.