That's all fine and good, but this response is entirely different from the blog's original argument that I was responding to. The original argument was "Icons should be based on real world objects because they give the user an immediate sense of what the icon is for." The argument here seems to be "People know what the current save icon means, so there's no reason to change it", and the thing is, this sort of "if it ain't broke, don't fix it" viewpoint is pretty antithetical to our jobs as interaction designers. Even if most people know what the save button means by convention, that doesn't rule out that might find a better icon, one that is strictly iconic and not skeuomorphic in any way (in fact, I think some better alternatives have already been found are are gaining in popularity).

So in summary, while I agree that it's sometimes fine to use an old icon if enough people understand what it means by convention, this is not a good reason to avoid using the newer, less skeuomorphic icons that the linked blog post was trying to argue against.