I can't say a lot about Leipzig but many german cities were rebuild far more car-centric then they were before. Public transportation, small streets and biking seemed outdated back then. A lot of medieval building were destroyed after 1945 to make room for cars. There's a good german (not subtitled) documentation about this topic [1].

The Nazis had the same attitude before. Cities had to be car-centric, that's why they moved on with the Autobahn and created Volkswagen. The obligation to use bike lanes (Radwegebenutzungspflicht) was issued under the Nazi regime. It was part of the fascist mindset that cities are made of concrete (instead of children playing in parks).

[1] http://www.ardmediathek.de/tv/Reportage-Dokumentation/Unsere...

Leipzig was rebuilt with essentially the same layout as before the war. If anything, additional space was used for larger roads.

Here is a video comparing a tram ride through Leipzig in 1992 with one in 1931:

https://www.youtube.com/watch?v=YX4wGWzWqBk

The way forward for the midwest is clear, then.