It's thanks to a lot more than just that infrastructure.
1 taxes, cost of fuel
2 culture (USA views bikes as for kids and tree-huggers)
3 density of urban areas
4 layout/zoning of urban areas (i.e. no ring of suburbia, shopping/strip malls around cities)
5 probably others that I'm not aware of
The infrastructure doesn't work without 3 and 4, and probably doesn't work without 2.
No, in the same way that people will not start smoking if they have to use mandatory safety goggles. Of course this kind of method depends on two things:
1) how critical the activity is to people's lives (cycling: low, driving: high)
2) how funny you look with the safety item on (...)
