I think that's largely because you probably don't run nuclear centrifuges located in Iran. Stuxnet was an extremely targeted virus.
Not arguing the other points about sandboxing. I think it's a great idea. I go further and recommend VMs that can be easily reverted to known good states. Personally, I don't allow windows systems on my home network, but that's because I'm a Unix bigot, and it's my network, so I get to make the rules. :-)
Running a VM is a good alternative and just as effective, but my argument here has been for the masses of home users who generally do not have the resources or knowledge to deal with virtualization... as simple as it may seem for us.
My point on Stuxnet was directed at the ridiculous rantings of the OP... it was one of his (incorrect) "examples" of why a sandbox won't help. I was merely trying to make some who may not be aware that there is an application available to them (It's not freeware, by the way) that can defeat almost every virus and malware application that they might encounter.
Which of course is why...
"This attack from an unknown source but likely related to Stuxnet, disabled one of the lists and thereby interrupted an important source of information for power plants and factories.[24]"
Oops.
And then there's the more general issue of the Stuxnet / Duqu / Flame methodology being reverse engineered and COPIED, presumably by some entity operating in a framework of governance that is not constrained by our specified pupose for American governance:
"TO SECURE THESE RIGHTS, governments are instituted among men.".