Living in Germany, I'm sure you see that that's neither easy nor something that happens automatically. Parallel societies exist and are growing. Maybe it would

Living in Germany, I'm sure you see that that's neither easy nor something that happens automatically. Parallel societies exist and are growing. Maybe it would be different if you didn't have large cultural groups who could form them? But then again, there aren't any Polish parallel societies in Germany (and ~2% immigrated or have an ancestor that came from Poland), and after a generation, you can only tell them apart from the rest of the population by their last name.