Europe has a population density twice that of the 48 lower US states. In addition, roughly a third of all people in the US live in a mere 500 cities (if you acc

Europe has a population density twice that of the 48 lower US states. In addition, roughly a third of all people in the US live in a mere 500 cities (if you account for metro areas, that number increases). Even if those cities had great public transit, it would leave the remaining areas far less populated in reality. Less than 30 people per square mile is very common outside cities with a lot of midwest states having something like 5-7 people per square mile (or less). It may be hard for people in many places to grasp, but even in eastern states there are many, many areas where you could pick a direction and walk many miles without seeing anyone. Below a certain population density (likely in the hundreds to low thousands per square mile), public transportation simply is not feasible.