If the demostics went metric they could get a little more precision in the manufacturing process.
American laborers do not have the same "Attention to Detail" as the Asian and European workers. "Good enough for Government work" doesn't fly overseas. Fit and finish is drastically different. Domestic tolerances are bigger, makes for easier manufacturing and assembly. Take the gap of the hood to the fender on most any domestic mainstream car and it is not equal, then look at the Japanese and Euro cars evenly spaced. Its this type of quality, or lack of, that represents the overall quality of the marque.
As Proud as we are to be American we do not have the same standards as do the "enemies". Most cars will be nice and tight for 40-50k miles but thats where the long term quality really begins to show.
While most Foreign vehicles have evolved and transformed dramatically for the sake of improvement the domestics have basically remained on the same/similar platforms for decades.