I think for the Americans, contributing data feels too much like work which would violate their idea of letting the free market do its thing. Where would the world go if people just did things for free? Same as with self check-outs, you ain't gonna do that work yourself if you're not getting a discount!

To be fair, contributing to OSM is more work in America. You have to drive every where and you technically aren't allowed to use other maps as a source (I don't know if that's ever followed though)