It's pretty ridiculous that somebody who earns more than 99% of Americans should become a stand-in for the average working man. The picture becomes a little more clear in this interview with Katie Couric, in which Joe the Plumber admits he doesn't actually earn $250,000 a year:
COURIC: Well, he supposedly will raise taxes only on people who make over $250,000 a year. Would you be in that category?
WURZELBACHER: Not right now at presently, but, you know, question, so he's going to do that now for people who make $250,000 a year. When's he going to decide that $100,000 is too much, you know? I mean, you're on a slippery slope here. You vote on somebody who decides that $250,000 and you're rich? And $100,000 and you're rich? I mean, where does it end? You know, that's - people got to ask that question.
In the same interview, he says that Barack Obama did a "tap dance... almost as good as Sammy Davis Junior." But Joe the Plumber is the one who lied about the central premise of his question to Obama. So the whole premise that made Joe the Plumber the icon of the debate turns out to be made up. I don't think reporters should start investigating the details of his life or anything. But if he's going to freely admit that he just made up the one fact that gave his story any political salience, then that's pretty relevant.