EDIT: to clarify, there are also examples where increased foreign industry will benefit America. For instance, if Kuwait doubles its productivity, oil imports to the U.S. will be much cheaper. But my point still stands that this is not also the case. Increased productivity from other countries can be positive or negative to America, depending on the specific situation.
Free-trade policies tend to be most beneficial to the market incumbents; but I would note that even when a foreign company simply comes in and exploits cheap labor, the workers will get better wages, and even if that doesn't directly benefit their own lives, it can give their children a better lifestyle and education.
The single biggest thing to happen in the last few decades is a couple of billion people (re-)joining the world economy (the PRC, India, the former Soviet Union, etc.).
To the extent a lot of recent manufacturing is satisfying basic needs we take for granted, e.g. refrigerators, isn't that likely to be all to the better?
What I'm saying here is that this gets complicated. Economies of scale are likely to give the manufacturers in the PRC the edge in supplying the world's demand for refrigerators, but on the other hand their increased demand for say aircraft and especially jet and turboprop engines is directly to our advantage.
Or perhaps I should say, this isn't a simple matter of winners or losers at this gross a level (PRC vs. US, US vs. the world). I expect the share of US manufacturing vs. the world's to go down during this period and I expect the trajectory of PRC manufacturing to be wild compared to ours.