Anecdotally, from working and living in Germany, I've very much noticed that Germans are better with time management, and work shorter hours and get more done compared with my home country (Australia).
I'd be surprised to see contrary evidence, though it's certainly a possibility. But the article you linked does not appear to demonstrate much of substance in terms of present day productivity.
Stereotypes can be damaging, sure, but when discussing certain aspects of a culture they can be true and based on cultural norms. I don't think we should broadly dismiss them when used in the right context, and not in a discriminatory fashion.