Not unions solely, but as other commenters have pointed out, the cost of labor more generally is what did it. And the comparative cost of labor in e.g. China v

Not unions solely, but as other commenters have pointed out, the cost of labor more generally is what did it. And the comparative cost of labor in e.g. China vs. US is driven by the balance of trade. Expensive labor is the price the US pays to run a trade deficit