Tyler Cowen takes issue with the Europe comparison:
Why do many European nations have higher mobility? Putting ethnic and demographic issues aside, here is one mechanism. Lots of smart Europeans decide to be not so ambitious, to enjoy their public goods, to work for the government, to avoid high marginal tax rates, to travel a lot, and so on. That approach makes more sense in a lot of Europe than here. Some of the children of those families have comparable smarts but higher ambition and so they rise quite a bit in income relative to their peers. (The opposite may occur as well, with the children choosing more leisure.) That is a less likely scenario for the United States, where smart people realize this is a country geared toward higher earners and so fewer smart parents play the “tend the garden” strategy.
Quiggin isn't persuaded:
Cowen’s post is an exercise in defending the indefensible, and its weaknesses reflect that. As Mitt Romney’s tax returns show, wealthy Americans have the rules rigged in their favor from day one. And that’s assuming they obey the rules. Unlike the poor, they can mostly cheat with impunity. In these circumstances, it’s unsurprising that US inequality is so deeply entrenched. The only surprise is the suddenness with which the facts have become common knowledge.
(Chart via Jason Linkins)