Average commute time in the us is lower than almost all of europe (https://goo.gl/r8DJqz) and public transport not only needs billions in investment to be built but there are very few places where it doesn't run on subsidies. So yeah you're asking americans to a) take longer to get to work b) constantly subsidise a system that will keep on losing money. Based on the political makeup of the country i'd say you can keep on dreamin' :)