Europeans tend to have cities that have been around much longer than cars have, and you can see it in the design - they were built back when horses were the fastest mode of transportation.
Many small American towns were built after the introduction of the automobile (or at least significant chucks of the towns were).
Trying to undo history, or even taking a new mode of design is extraordinarily difficult. The discussion threads on this post seems to highlight that difficulty, while many miss that root cause.