Sorry - NO. These aren't some super secret stealth aircraft needing special materials and billions of $ to develop. They are programming the same Windows targets using the same compilers, generating the same instructions using the same system calls. Yes they were clever to target the particular facility and to hide the code. But they didn't build anything that some other malicous hacker couldn't build.
"And the zero-day exploits used in these attacks are unknown to antivirus companies by definition."
I must try that excuse. The bugs in my software are by definition unknown so I can't be expected to have fixed them.
So exactly what is the point of virus scanners? If all they are doing is checking for the obvious signatures in email attachments called "naked pictures of whoever readme.exe" to look for well known threats isn't the solution simply for the user to not be a moron?