Response to "Buying Courtesy"

In this article the arthor writes about the experience he/she had in a Wawa. There are many people who ignore common courtesy needed in convenient stores such as Wawas, and the American society is no longer a friendly one like it used to be in the 1950's.
The writer poses a question about why the society is changing this way. He/she focuses on the people who do not show the common courtesy, such as holding doors for others, giving simple greetings, and waiting patiently for their orders. I can clearly see the people in my mind's eye, the people with nicely fitted slacks, neatly buttoned shirts, and clean haircuts, and constantly talking on their phones.
However, a different question comes in my mind. Is it because the people are just getting rude or is there a hidden reason underneath the surface? I grew up in a different country where "common courtesy" accepted in America wouldn't be accepted. People try not to interfere with others and not to be nosing in others' business. This being the cultural trend, they usually avoid contact with others and small talks.
People might think not giving simple greetings is rude, but looking at it objectively, I'd say it's just a cultural trend generated by the cities. People are looking for a more efficient way to survive in the cities, and that way of life comes off as "rude", but it's just a better way to live in the city. That's probably why those people get the jobs in big companies and wear nice clothes. The appearance and their impatience may lead us to be prejudiced against those people, but the few seconds might be the difference between job and no job for them, as the phone calls they make might be the difference between promotion and weekend shift. The trend we see is not caused by individuals' rudeness, but by a trend of growing cities.