I think you are wrong here, what you said is mostly about how it is in big cities versus the rural areas, same thing is in Europe. You will not find a lot of mass transit in European countryside, sure there are buses and trains probably more abundant than in USA but be prepared to walk a few kilometers to the nearest station.
Your point would make sense if USA had high-speed trains linking big cities but it doesn't, and the train routes that do exist experience all sorts of delays which makes people choose planes even for shorter distances under 500 km which would take ~2 hr on high speed train.