The bigger point is, what is manufacturing as percentage of US gross product. And also, could such a sector, as in the past, be large enough to eliminate (or prevent) a welfare state, thus encouraging the return of the family and keeping all Marxist social policies at bay.
Developed countries tend to have around 25% of their GDP in manufacturing but only 20% of their employees in manufacturing.
The number of employees per unit of manufacturing has been dropping for years.
One take:
http://www.bloomberg.com/news/articles/2014-04-28/why-factory-jobs-are-shrinking-everywhere