Why do German automakers thrive there, then? Always found it odd that some of the most sophisticated cars in the world are made in a country where supposedly no one has any use for them.
Yes, 90% Of Germans live in small- to medium-size cities (I.e., not in Berlin, Cologne, Hamburg, and Munich). Berlin in particular has exceptional public transport.
Don't forget the Ruhr area on your list which has another 8% of people. I would say you could live without a car in most major cities (these are the 79 with more than 100k inhabitants). About a third of Germans live there. When it gets smaller than this relying on public transport is getting more and more inconvenient. The third that lives in small towns or rural areas definitely needs a car — or rather two — per household.