It's how the city was planned.
European cities have small, walkable centers, the mid-density around that, then instead of suburbs, they have a lot of higher density hamlets around them.
Also - they don't have horrific winters in which walking/biking is a pain.
So - even for Frankfurt, which has a bunch of US style high-rises in the middle ... you can comfortably walk many places, and bike almost all of them, any time of year.
Combine that with widespread and completely integrated public transit (without goons, slubs and idiots ruining them) - it works extremely well.
Most North American cities are designed for cars: long blocks, no walkable 'high streets', very wide streets, less density, less public transport ... and often a harsh winter which makes it really uncomfortable for 5-ish months a year.
It will take more than bike lanes to change the nature of culture.