Back then, most people were born, lived and died in the same city/county. The pickings for potential mates were few, and so you basically had to find someone "good enough" and stick with it. Of course increased mobility increased the number of potential mates, and now with the Internet, the illusion of "many fish in the sea", make it so that people hold out until they find their "soulmate", which of course in the vast majority of cases, never happens.
That’s a good perspective on another aspect of what technological innovation did to change America. Increased mobility, first via railroads, then interurban trollies, and finally via the automobile certainly changed things. I hadn’t thought about that aspect before.
Technology does have a way of changing things in ways nobody could have imagined:
* transportation (as you point out)
* hormonal contraceptives
* global instantaneous communications