Canada has now overtaken the U.S. to become the nation with the wealthiest middle class according to this Globe article, Canada matched the U.S. in median income in 2010 and we have now surpassed the U.S. This is part due to an almost 20% growth income since 2000 while U.S. only had 0.3%, many Western European countries also saw better growth.
According to the NYT it is: “Because the total bounty produced by the American economy has not been growing substantially faster here in recent decades than in Canada or Western Europe, most American workers are left receiving meagre raises,” the New York Times report says. “Finally, governments in Canada and Western Europe take more aggressive steps to raise the take-home pay of low- and middle-income households by redistributing income.”
I have to say I am not surprised that the American economy stagnated income wise. Sure some individual states have seen growth but overall the U.S. is in the same place it was in 2000. You can't blame one party or president either since both the Republicans and Democrats have had power during that time.