Folks want to blame corporations for it a fair amount of the time, but every time I get into the dialog, and burrow down to the bedrock, I find the same two culprits: corporate taxation and government regulation.
EVERY time.
As much as there are people out there — and it always kinda seems to be the SAME people, oddly — who try to blame "greedy evil corporations," the actual facts always point back to Uncle Sam and his satellite cronies in the 50 states.
When Japan eliminates their corporate tax, which they were already talking about doing BEFORE they got hit with the big earthquake and tsunami, the United States will have the most overbearing corporate tax and regulation environment in the known universe; ALL of that — ever single letter — imposed by government; local, state, and federal.
With that as background, I think the more intelligent question is not "Who's responsible for the destruction of U. S. Manufacturing," it's "How have American companies managed to keep any manufacturing jobs here in this country?"
Don't piss down my back and tell me its raining. There are plenty of right to work states in the South where manufacturing can be done profitably.