When in college, I thought that all the foreign kids were really smart.
Then I finally realized that only the very brightest are privileged to come to the US to study (wealthy foreigners excepted).

I spoke to a Chinese friend of mine and asked how it came to be that he got to come to the US to study.
He replied that it was kind of like a contest. During each "grade", the "winners" (aka highest achievers) were allowed to participate in the next "grade" (level) of learning/school.
The "losers" were "out"...done with school for good. They were not then and never would be allowed to advance to the next level. They became the field hands and laborers for many of the manual/non-educated jobs around the country.

He expanded on this as being a HUGE motivator for him to go to great lengths to achieve success....even greater than any dishonor his failure might bring his family.

I have not seen this level of motivation very often in US students.