I'll suggest the change is the globalization of the US economy. The US effectively added a billion low income workers to its economy, and that group has seen l

I'll suggest the change is the globalization of the US economy. The US effectively added a billion low income workers to its economy, and that group has seen large relative gains in income over the past few decades. Some of those gains were, as predicted, effectively a transfer of wealth from the US middle class. Although newspaper articles about globalization are now relatively rare, it is a day to day reality that I'm sure many HN readers live and breathe. While the massive destruction of poverty in the developing world has been an unqualified good, it was no secret that the trade-off was stagnating wages in the developed world until the developing world 'caught up'. There has been a reduction in income inequality, but it has been at the global scale. The US is not a gated community like Scandinavia. The US is deeply embedded in the global economy. Any attempt to ignore the global economic perspective will be misleading at best and ultimately futile.