Then count on their being a financial reason for do so.
Of course, but automation (really, robotics) has allowed both U.S. and Japanese auto companies, and firms in many other manufacturing industries, to operate plants here profitably (rather than exclusively in China - or Mexico - where the relatively low-cost labor resides). This is the driving force behind the decline in manufacturing employment. As other posters have noted, our manufacturing sectors produces more stuff now than ever; it just does so with fewer workers.