While I have no formal study to back this up, my theory is that in the US, motor vehicles were first introduced as a luxury for a select few, then something of a more utilitarian necessity, and over time became the widespread everyday, taken for granted phenomenon it is today. Thus, our culture has had over a century to evolve customs and courtesies of the road, traffic laws driver's ed programs, etc. Kids grew up as passengers with mom or dad driving and learned some of this by osmosis, and over time, road networks, gas stations, and other infrastructure grew in concert with motor vehicle usage.
In Korea, and presumably some other Asian countries, motor vehicles remained toys of the wealthy for a long time until sudden burgeoning economies in the 80s led to the immediate widespread availability of cars without any slow evolution or inculcation of driving culture, or the opportunity to build supporting road networks. You had young adults as new car buyers who came from house holds that rode trains, busses or in rural areas, ox carts all through their childhood. Without learning or developing good driving habits, they merely reinforced bad habits every time they got behind the wheel...and now they're teaching the next generations to drive.
Just my theory....
I worked at a plant on the Korea east coast in the late 90’s.
We had a lot of engineers that grew up and got their degrees in Seoul. Most had never been in a private car till they came to the jobsite.
In the United States we teach our children to drive before we teach them how to drink.
-PJ