Well, of course she's not going to find those stereotypes at a college. Those are the students who did well in high school and typically know how to manage their school-life.
But, if you look at American HS students in general there is an over-confidence and lack of effort.
As an undergraduate, I used to be an English-tutor for foreign graduate students. I probably helped about 10 students over the course of my service. Seven of them were from Asian countries, including Korea, Japan, Taiwan, China, and HK. Three of these students were in Doctorate programs, the others were working toward masters degrees in the sciences. The three that were pursuing doctorates in things like economics and literature were all eventually asked politely to leave after being awarded their master's degrees. The passive system of learning that the author mentions works well for things like electrical engineering, but the Ph.D. programs in the softer sciences and the liberal arts require a much more agressive approach. The few European students I knew did fine.
"I would make all my subordinates Americans and start a hamburger joint with great atmosphere. "