If we have a weaker USD, doesn't that make US manufacturers' costs increase (measured in USD), and their finished goods prices increase (measured in USD), resulting in global prices staying about the same (measured in whatever foreign currency).

I mean, labor prices won't move quickly, and existing capital equipment was purchased with stronger dollars, but eventually new equipment will be needed at higher cost, and people will demand higher wages to meet their previous spending power, and anyway, american manufacturing tries to reduce labor as far as possible.