QC shouldn't be dependent on origin of manufacture, but on employee training.
I agree with everything else you wrote, but local culture plays a role in manufacturing. I'm originally from Australia, and we have an expression there: "she'll be right". It means everything will be alright, so don't worry. For years we manufactured cars, and they had lots of problems because the "she'll be right" mentality made its way into the cars. I can't picture "she'll be right" being part of the Japanese culture, which is part of the reason they make flawless guitars. I buy Toyota cars now, although when I want a decent cheaper version, I buy Hyundai's. I don't buy Australian or American cars. There are exceptions of course: Australian and American-made guitars are excellent. Maybe Germany should make guitars too.