The automobile made a difference in the mobility of society. Cars led to trucks, making moving a home easier. Families used to stay near each other and the culture of the inhabitants stayed intact for generations. But there had been trains in use in this country for a hundred years by the 20th century, so people could travel to major metropolitan areas when they wanted to see art or for any other reason. There have been adventurous people traveling since the country was founded without which there would not have been the westward expansion. That was real exposure to different cultures. Explain.
Yes, I agree that cars and trains increased mobility exponentially, but even with those vehicles available, not everyone would travel or move. It is not so much of a logistical problem as it is a mental attitude, in my opinion.
Horace Greeley said it well: "Go west, young man", but that spirit was there long before he is credited with his famous saying. [Curiously, Wikipedia says that it was John B. L. Soule, an ...
In a 281 word solution, the response explains that it was not specifically the automobile, but a much more basic attitude towards western expansion.