Additional factors are distance and climate, for instance compared to the cities in northern Europe that are famous for bike use. Most of the US gets hotter and colder than those cities, and we have social customs that discourage being sweaty when you arrive at work. Also, our typical commuting distances are longer. When people in Amsterdam have commutes longer than a few miles, they park their bikes at the nearest train station, and ride the train into town.

Thus the "infrastructure" could include public transportation. In my spouse's case, public transit encouraged her to ride her bike because it provides an alternative on days when it's too crappy to ride.