For years, Washington has made increasing manufacturing employment a priority, hoping to engineer a return to the time when high-school graduates could use factory jobs as a route to the middle class. Sadly, that isn’t going to happen. Of the 5.7 million manufacturing jobs that disappeared in the 2000s, only 870,000 have returned so far, according to the Bureau of Labor Statistics, and the claim that millions more are coming back is nothing more than a myth.