I'm not an MBA and I'm prepared to believe in your assertion that MBA has not much value, but your arguments are not very relevant. For starters, I don't know

I'm not an MBA and I'm prepared to believe in your assertion that MBA has not much value, but your arguments are not very relevant. For starters, I don't know that American companies are as good as German and Japanese companies. US is measurably wealthier than both of these countries, at least in terms of GDP per capita. Maybe US large companies are more efficient. But even if assume large companies in those countries are similarly efficient, there are way too many differences between US and Japan besides "MBA density". It could be the case that Japanese companies hold their own despite the lack of MBAs. In fact, I do believe they do well despite the custom of treating fresh undergrads as useless, insisting on an archaic seniority system, etc.