This has also been a thorn in my side for a long time. Extension cords allow any bonehead to play Electrician - think about it: they give someone the legal ability to run power without any form of guidance. "Cable size? What's that? They make different cable sizes? Why? I'll just get the cheapest one..."
I actually provide a list of extension cord "dos and do-nots" to customers that are planning some sort of event, but would bet they often don't even take a gander at it.
I think it's all about marketing and pricing. Joe-schmoe is not likely to spend the extra few bucks on a GFCI or even a breaker/fuse protected cable. And, in the event that it tripped, you can bet the wire cutters and black tape would come out to bypass that little "inconvenience".
You're right that this issue is more important than a lot of "product-placement" laws that are being pushed through the NEC. After all, isn't that their main objective - preventing fires? Some people up there seem to have misplaced their focus.
