That's just not true in many companies nowadays. E.g. in the automotive industry (which is 1/7 of the german economy) I have a growing number of colleagues who don't speak a word of German.
Well "growing numbers" vs. reall acceptance is quite a long way.
Possibly in Berlin, where is more alien friendly, to be able to get any job in English, in south, especiall south Bayern is quite difficult, even in IT ( which I really don't understant). Might be if all customers are in Germany, then there will be a gap somewhere, which someone has to fill and they don't really want or can.
In bigger companies ( like automotive, or even Siemens ), they do have customers and organisation from all over the world and English is the primary documentation and also common language.
I only wanted to say, that given a perfect candidate for a position, it might be rejected because it doesn't speak German.