Why I Don't Sell German Books in Germany

I write the books in English because most of my input comes on in English. I then need very good editors and proofreaders who, yeah, to make it nice,. The book and then Spanish is the same thing. In English and Spanish, it works 100% with more or less literal translation. But for example, I'm German. My German books are absolute failure. They're not selling. Do you know why? Maybe it's because you're actually not very German.