The article's point isn't that globalization (or policy) didn't play a role, it's that the premise of middle class downfall is false to begin with. See the section under the header "The American middle class was never hollowed out".
The middle class of the 1980s/1990s are the poor of today... the middle class of today are different people (and probably would have been upper class professionals in the past)
Those people who used to be middle class didn't just die off. There still here, a large demographic of the United States, and still very very angry. Our current political situation should make that obvious.
