The problem is, management requires stronger language skills than engineering.
While an engineer can usually get by with good English, a manager in a German company with German clients and German bosses also requires excellent command of German. I would think that this would equally apply to any other country and their native language.
Perhaps Germany is a bit unusual in that it fosters a strong small-company culture, with few levels of management. There is no "engineering ladder" in a company with only a single layer of management between engineers and CEO.
While an engineer can usually get by with good English, a manager in a German company with German clients and German bosses also requires excellent command of German. I would think that this would equally apply to any other country and their native language.
Perhaps Germany is a bit unusual in that it fosters a strong small-company culture, with few levels of management. There is no "engineering ladder" in a company with only a single layer of management between engineers and CEO.