Stupidity is not a problem that can be solved through technology.
At least Apple now has a service to protect stupid people against themselves, it's called the "App Store". You know, with the kind of approval system we've all been bitching about.
As far as I'm concerned, self-inflicted malware is about as big a security issue as running with scissors. To treat it as some external force that needs to be dealt with by manufacturers, OS-makers, anti-virus producers or even legislators just perpetuates the real problem, turning it into a perpetual arms race that can not possibly be won, but at some point may cost us the freedom to install anything we want on our computers.