1) Their management hierarchies only consist of MBA suits that think short term and treat their engineers like apes in a zoo. This frequently leads to engineers actually behaving like apes in a zoo.
2) German culture is deeply based on thinking in silos. They divide everything into boxes in order to organize it "the right way" and don't understand network effects that occur if you focus on building a great (software engineering) culture. Instead, they mindlessly copy-paste whatever fancy thing they see in a silicon valley context.
3) My hypothesis of why German IT products are almost always horrible is that they're rarely thinking from customer's (or developer's!) perspective. They may be proud of some specs of their products but the overall thing is then often just a bunch of related subsystems "pragmatically" tied up with some duct tape.
They still obviously don't understand why they're being outsmarted by Apple, Amazon, Google and others. They're aggressively arrogant and rather lobby the German gov't or cheat to achieve short-time success instead of reorganizing their structures to still be leading in 10 years.
I bet, they internally expect industry leading products 2 years after launch and then will quietly kill the whole thing when they realize that their bet was insane from the beginning.