Sure but every large city and many medium to small cities have mass transit via buses. Not technically trains but if we're talking passenger mass transit it's better than nothing. America isn't really a developing country when it comes to passenger service, that sort of insults everyone. India is a developing country and they pack so deep onto trains that they ride the roofs and hang off the sides. America had a very large passenger network at one time, which downsized because of the publics adoption of automobiles. It's very developed, you're ignoring cities that have a metropolis rail system like LA, Philly, etc. The cities that tend to have none at all are southern cities that got built up in the last 50ish years once AC became common place (Texas.) Even then I think some of those communities are pushing for some passenger rail service.

Thing to remember is we'll never have anything like Europes system because most European countries are the size of an American state. We have such vast distances between some major cities (new york to LA) that you can't reasonably expect a passenger rail system.