tptacek could probably weigh in with a much better explanation. The tradeoff for having AV is having a giant application in admin land which increases the surf

tptacek could probably weigh in with a much better explanation. The tradeoff for having AV is having a giant application in admin land which increases the surface area available for an attack. Combine this with the that fact you don't get much protection because a virus can just be modified until the AV doesn't detect it and AV's just aren't worth it. This trade off made sense 20 years ago because OS's were less secure so you were increasing your surface area by relatively less than you are now.