> International business class
    > is expensive, yes, typically
    > on the order of $8,000 to 
    > $10,000

The usual roundtrip flight price for flights Germany-Japan (as determined with hundreds of searches on Skyscanner) seems to be:

Economy: ~400 GBP

Premium Economy: ~1000 GBP

Business: ~1300 GBP

First: ~3700 GBP

So, the "$8000 to $10000" isn’t even in the same ballpark as First class, respectively business class.